chore(i8n,learn): processed translations (#41350)
* chore(i8n,learn): processed translations * fix: restore deleted test * fix: revert casing change Co-authored-by: Crowdin Bot <support+bot@crowdin.com>
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Nicholas Carrigan (he/him)
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@ -1,6 +1,6 @@
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---
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id: a9bd25c716030ec90084d8a1
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title: Chunky Monkey
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title: 分割数组
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challengeType: 5
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forumTopicId: 16005
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dashedName: chunky-monkey
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@ -8,11 +8,11 @@ dashedName: chunky-monkey
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# --description--
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Write a function that splits an array (first argument) into groups the length of `size` (second argument) and returns them as a two-dimensional array.
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请编写一个函数，该函数将一个数组（第一个参数）拆分成若干长度为 `size`（第二个参数）的子数组，并将它们作为二维数组返回。
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# --hints--
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`chunkArrayInGroups(["a", "b", "c", "d"], 2)` should return `[["a", "b"], ["c", "d"]]`.
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`chunkArrayInGroups(["a", "b", "c", "d"], 2)` 应返回 `[["a", "b"], ["c", "d"]]`。
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```js
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assert.deepEqual(chunkArrayInGroups(['a', 'b', 'c', 'd'], 2), [
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@ -21,7 +21,7 @@ assert.deepEqual(chunkArrayInGroups(['a', 'b', 'c', 'd'], 2), [
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]);
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```
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5], 3)` should return `[[0, 1, 2], [3, 4, 5]]`.
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5], 3)` 应返回 `[[0, 1, 2], [3, 4, 5]]`。
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```js
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assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5], 3), [
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@ -30,7 +30,7 @@ assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5], 3), [
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]);
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```
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5], 2)` should return `[[0, 1], [2, 3], [4, 5]]`.
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5], 2)` 应返回 `[[0, 1], [2, 3], [4, 5]]`。
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```js
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assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5], 2), [
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@ -40,7 +40,7 @@ assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5], 2), [
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]);
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```
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5], 4)` should return `[[0, 1, 2, 3], [4, 5]]`.
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5], 4)` 应返回 `[[0, 1, 2, 3], [4, 5]]`。
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```js
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assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5], 4), [
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@ -49,7 +49,7 @@ assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5], 4), [
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]);
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```
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6], 3)` should return `[[0, 1, 2], [3, 4, 5], [6]]`.
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6], 3)` 应返回 `[[0, 1, 2], [3, 4, 5], [6]]`。
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```js
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assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6], 3), [
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@ -59,7 +59,7 @@ assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6], 3), [
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]);
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```
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6, 7, 8], 4)` should return `[[0, 1, 2, 3], [4, 5, 6, 7], [8]]`.
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6, 7, 8], 4)` 应返回 `[[0, 1, 2, 3], [4, 5, 6, 7], [8]]`。
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```js
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assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6, 7, 8], 4), [
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@ -69,7 +69,7 @@ assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6, 7, 8], 4), [
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]);
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```
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6, 7, 8], 2)` should return `[[0, 1], [2, 3], [4, 5], [6, 7], [8]]`.
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`chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6, 7, 8], 2)` 应返回 `[[0, 1], [2, 3], [4, 5], [6, 7], [8]]`。
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```js
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assert.deepEqual(chunkArrayInGroups([0, 1, 2, 3, 4, 5, 6, 7, 8], 2), [
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@ -1,6 +1,6 @@
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---
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id: 56533eb9ac21ba0edf2244b3
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title: Convert Celsius to Fahrenheit
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title: 将摄氏度转换为华氏度
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challengeType: 1
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forumTopicId: 16806
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dashedName: convert-celsius-to-fahrenheit
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@ -8,43 +8,43 @@ dashedName: convert-celsius-to-fahrenheit
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# --description--
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The algorithm to convert from Celsius to Fahrenheit is the temperature in Celsius times `9/5`, plus `32`.
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将摄氏度转换为华氏度的计算方式为：摄氏度乘以 `9/5` 然后加上 `32`。
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You are given a variable `celsius` representing a temperature in Celsius. Use the variable `fahrenheit` already defined and assign it the Fahrenheit temperature equivalent to the given Celsius temperature. Use the algorithm mentioned above to help convert the Celsius temperature to Fahrenheit.
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输入参数 `celsius` 代表一个摄氏度的温度。 使用已定义的变量 `fahrenheit`，并赋值为相应的华氏度的温度值。 根据上述转换公式来进行转换。
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# --hints--
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`convertToF(0)` should return a number
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`convertToF(0)` 应返回一个数字。
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```js
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assert(typeof convertToF(0) === 'number');
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```
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`convertToF(-30)` should return a value of `-22`
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`convertToF(-30)` 应返回 `-22`。
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```js
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assert(convertToF(-30) === -22);
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```
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`convertToF(-10)` should return a value of `14`
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`convertToF(-10)` 应返回 `14`。
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```js
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assert(convertToF(-10) === 14);
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```
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`convertToF(0)` should return a value of `32`
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`convertToF(0)` 应返回 `32`。
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```js
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assert(convertToF(0) === 32);
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```
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`convertToF(20)` should return a value of `68`
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`convertToF(20)` 应返回 `68`。
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```js
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assert(convertToF(20) === 68);
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```
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`convertToF(30)` should return a value of `86`
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`convertToF(30)` 应返回 `86`。
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```js
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assert(convertToF(30) === 86);
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---
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id: adf08ec01beb4f99fc7a68f2
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title: Falsy Bouncer
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title: 过滤数组中的假值
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challengeType: 5
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forumTopicId: 16014
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dashedName: falsy-bouncer
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@ -8,33 +8,33 @@ dashedName: falsy-bouncer
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# --description--
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Remove all falsy values from an array.
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从数组中移除所有假值（falsy values）。
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Falsy values in JavaScript are `false`, `null`, `0`, `""`, `undefined`, and `NaN`.
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JavaScript 中的假值有 `false`、`null`、`0`、`""`、`undefined`、`NaN`。
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Hint: Try converting each value to a Boolean.
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提示：可以考虑将每个值都转换为布尔值（boolean）。
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# --hints--
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`bouncer([7, "ate", "", false, 9])` should return `[7, "ate", 9]`.
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`bouncer([7, "ate", "", false, 9])` 应返回 `[7, "ate", 9]`。
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```js
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assert.deepEqual(bouncer([7, 'ate', '', false, 9]), [7, 'ate', 9]);
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```
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`bouncer(["a", "b", "c"])` should return `["a", "b", "c"]`.
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`bouncer(["a", "b", "c"])` 应返回 `["a", "b", "c"]`。
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```js
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assert.deepEqual(bouncer(['a', 'b', 'c']), ['a', 'b', 'c']);
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```
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`bouncer([false, null, 0, NaN, undefined, ""])` should return `[]`.
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`bouncer([false, null, 0, NaN, undefined, ""])` 应返回 `[]`。
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```js
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assert.deepEqual(bouncer([false, null, 0, NaN, undefined, '']), []);
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```
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`bouncer([null, NaN, 1, 2, undefined])` should return `[1, 2]`.
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`bouncer([null, NaN, 1, 2, undefined])` 应返回 `[1, 2]`。
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```js
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assert.deepEqual(bouncer([null, NaN, 1, 2, undefined]), [1, 2]);
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@ -1,6 +1,6 @@
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---
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id: a789b3483989747d63b0e427
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title: Return Largest Numbers in Arrays
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title: 找出多个数组中的最大数字
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challengeType: 5
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forumTopicId: 16042
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dashedName: return-largest-numbers-in-arrays
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@ -8,13 +8,13 @@ dashedName: return-largest-numbers-in-arrays
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# --description--
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Return an array consisting of the largest number from each provided sub-array. For simplicity, the provided array will contain exactly 4 sub-arrays.
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请返回一个数组，该数组由参数中每个子数组中的最大数字组成。 为简单起见，给出的数组总会包含 4 个子数组。
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Remember, you can iterate through an array with a simple for loop, and access each member with array syntax `arr[i]`.
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别忘了，你可以通过 for 循环遍历一个数组，并用 `arr[i]` 的写法来访问数组中的元素。
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# --hints--
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`largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]])` should return an array.
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`largestOfFour([[4, 5, 1, 3], [13, 27, 18, 26], [32, 35, 37, 39], [1000, 1001, 857, 1]])` 应返回一个数组。
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```js
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assert(
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);
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```
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`largestOfFour([[13, 27, 18, 26], [4, 5, 1, 3], [32, 35, 37, 39], [1000, 1001, 857, 1]])` should return `[27, 5, 39, 1001]`.
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`largestOfFour([[13, 27, 18, 26], [4, 5, 1, 3], [32, 35, 37, 39], [1000, 1001, 857, 1]])` 应返回 `[27, 5, 39, 1001]`。
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```js
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assert.deepEqual(
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@ -41,7 +41,7 @@ assert.deepEqual(
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);
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```
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`largestOfFour([[4, 9, 1, 3], [13, 35, 18, 26], [32, 35, 97, 39], [1000000, 1001, 857, 1]])` should return `[9, 35, 97, 1000000]`.
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`largestOfFour([[4, 9, 1, 3], [13, 35, 18, 26], [32, 35, 97, 39], [1000000, 1001, 857, 1]])` 应返回 `[9, 35, 97, 1000000]`。
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```js
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assert.deepEqual(
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);
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```
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`largestOfFour([[17, 23, 25, 12], [25, 7, 34, 48], [4, -10, 18, 21], [-72, -3, -17, -10]])` should return `[25, 48, 21, -3]`.
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`largestOfFour([[17, 23, 25, 12], [25, 7, 34, 48], [4, -10, 18, 21], [-72, -3, -17, -10]])` 应返回 `[25, 48, 21, -3]`。
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```js
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assert.deepEqual(
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@ -1,6 +1,6 @@
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---
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id: 579e2a2c335b9d72dd32e05c
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title: Slice and Splice
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title: Slice 与 Splice
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challengeType: 5
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forumTopicId: 301148
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dashedName: slice-and-splice
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@ -8,29 +8,29 @@ dashedName: slice-and-splice
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# --description--
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You are given two arrays and an index.
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本挑战的输入参数为两个数组和一个索引值。
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Copy each element of the first array into the second array, in order.
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将第一个数组中的所有元素依次复制到第二个数组中。
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Begin inserting elements at index `n` of the second array.
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请注意，你需要从第二个数组索引值为 `n` 的地方开始插入。
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Return the resulting array. The input arrays should remain the same after the function runs.
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最后，请返回插入元素后的数组。 作为输入参数的两个数组在函数执行前后应保持不变。
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# --hints--
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`frankenSplice([1, 2, 3], [4, 5], 1)` should return `[4, 1, 2, 3, 5]`.
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`frankenSplice([1, 2, 3], [4, 5], 1)` 应返回 `[4, 1, 2, 3, 5]`。
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```js
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assert.deepEqual(frankenSplice([1, 2, 3], [4, 5], 1), [4, 1, 2, 3, 5]);
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```
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`frankenSplice([1, 2], ["a", "b"], 1)` should return `["a", 1, 2, "b"]`.
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`frankenSplice([1, 2], ["a", "b"], 1)` 应返回 `["a", 1, 2, "b"]`。
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```js
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assert.deepEqual(frankenSplice(testArr1, testArr2, 1), ['a', 1, 2, 'b']);
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```
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`frankenSplice(["claw", "tentacle"], ["head", "shoulders", "knees", "toes"], 2)` should return `["head", "shoulders", "claw", "tentacle", "knees", "toes"]`.
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`frankenSplice(["claw", "tentacle"], ["head", "shoulders", "knees", "toes"], 2)` 应返回 `["head", "shoulders", "claw", "tentacle", "knees", "toes"]`。
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```js
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assert.deepEqual(
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);
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```
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All elements from the first array should be added to the second array in their original order.
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第一个数组中的所有元素都应按原始顺序添加到第二个数组中。
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```js
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assert.deepEqual(frankenSplice([1, 2, 3, 4], [], 0), [1, 2, 3, 4]);
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```
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The first array should remain the same after the function runs.
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函数运行后，第一个数组应保持不变。
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```js
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frankenSplice(testArr1, testArr2, 1);
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assert.deepEqual(testArr1, [1, 2]);
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```
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The second array should remain the same after the function runs.
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函数运行后，第二个数组应保持不变。
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```js
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frankenSplice(testArr1, testArr2, 1);
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@ -1,6 +1,6 @@
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---
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id: a24c1a4622e3c05097f71d67
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title: Where do I Belong
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title: 找出元素在排序后数组中的索引
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challengeType: 5
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forumTopicId: 16094
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dashedName: where-do-i-belong
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@ -8,105 +8,105 @@ dashedName: where-do-i-belong
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# --description--
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Return the lowest index at which a value (second argument) should be inserted into an array (first argument) once it has been sorted. The returned value should be a number.
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数组（第一个参数）在排序后，将一个值（第二个参数）插入该数组，并使数组保持有序。返回这个新插入元素的最小索引值。 返回值应为一个数字。
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For example, `getIndexToIns([1,2,3,4], 1.5)` should return `1` because it is greater than `1` (index 0), but less than `2` (index 1).
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例如，`getIndexToIns([1,2,3,4], 1.5)` 应该返回 `1` 因为1.5 大于 `1`（索引为 0）且小于 `2`（索引为 1）。
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Likewise, `getIndexToIns([20,3,5], 19)` should return `2` because once the array has been sorted it will look like `[3,5,20]` and `19` is less than `20` (index 2) and greater than `5` (index 1).
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同样地，`getIndexToIns([20,3,5], 19)` 应该返回 `2`。 因为数组排序后会变成 `[3,5,20]`，而 `19` 小于 `20`（索引为 2）且大于 `5`（索引为 1）。
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# --hints--
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`getIndexToIns([10, 20, 30, 40, 50], 35)` should return `3`.
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`getIndexToIns([10, 20, 30, 40, 50], 35)` 应返回 `3`。
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```js
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assert(getIndexToIns([10, 20, 30, 40, 50], 35) === 3);
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```
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`getIndexToIns([10, 20, 30, 40, 50], 35)` should return a number.
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`getIndexToIns([10, 20, 30, 40, 50], 35)` 应返回一个数字。
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```js
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assert(typeof getIndexToIns([10, 20, 30, 40, 50], 35) === 'number');
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```
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`getIndexToIns([10, 20, 30, 40, 50], 30)` should return `2`.
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`getIndexToIns([10, 20, 30, 40, 50], 30)` 应返回 `2`。
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```js
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assert(getIndexToIns([10, 20, 30, 40, 50], 30) === 2);
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```
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`getIndexToIns([10, 20, 30, 40, 50], 30)` should return a number.
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`getIndexToIns([10, 20, 30, 40, 50], 30)` 应返回一个数字。
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```js
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assert(typeof getIndexToIns([10, 20, 30, 40, 50], 30) === 'number');
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```
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`getIndexToIns([40, 60], 50)` should return `1`.
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`getIndexToIns([40, 60], 50)` 应返回 `1`。
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```js
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assert(getIndexToIns([40, 60], 50) === 1);
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```
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`getIndexToIns([40, 60], 50)` should return a number.
|
||||
`getIndexToIns([40, 60], 50)` 应返回一个数字。
|
||||
|
||||
```js
|
||||
assert(typeof getIndexToIns([40, 60], 50) === 'number');
|
||||
```
|
||||
|
||||
`getIndexToIns([3, 10, 5], 3)` should return `0`.
|
||||
`getIndexToIns([3, 10, 5], 3)` 应返回 `0`。
|
||||
|
||||
```js
|
||||
assert(getIndexToIns([3, 10, 5], 3) === 0);
|
||||
```
|
||||
|
||||
`getIndexToIns([3, 10, 5], 3)` should return a number.
|
||||
`getIndexToIns([3, 10, 5], 3)` 应返回一个数字。
|
||||
|
||||
```js
|
||||
assert(typeof getIndexToIns([3, 10, 5], 3) === 'number');
|
||||
```
|
||||
|
||||
`getIndexToIns([5, 3, 20, 3], 5)` should return `2`.
|
||||
`getIndexToIns([5, 3, 20, 3], 5)` 应返回 `2`。
|
||||
|
||||
```js
|
||||
assert(getIndexToIns([5, 3, 20, 3], 5) === 2);
|
||||
```
|
||||
|
||||
`getIndexToIns([5, 3, 20, 3], 5)` should return a number.
|
||||
`getIndexToIns([5, 3, 20, 3], 5)` 应返回一个数字。
|
||||
|
||||
```js
|
||||
assert(typeof getIndexToIns([5, 3, 20, 3], 5) === 'number');
|
||||
```
|
||||
|
||||
`getIndexToIns([2, 20, 10], 19)` should return `2`.
|
||||
`getIndexToIns([2, 20, 10], 19)` 应返回 `2`。
|
||||
|
||||
```js
|
||||
assert(getIndexToIns([2, 20, 10], 19) === 2);
|
||||
```
|
||||
|
||||
`getIndexToIns([2, 20, 10], 19)` should return a number.
|
||||
`getIndexToIns([2, 20, 10], 19)` 应返回一个数字。
|
||||
|
||||
```js
|
||||
assert(typeof getIndexToIns([2, 20, 10], 19) === 'number');
|
||||
```
|
||||
|
||||
`getIndexToIns([2, 5, 10], 15)` should return `3`.
|
||||
`getIndexToIns([2, 5, 10], 15)` 应返回 `3`。
|
||||
|
||||
```js
|
||||
assert(getIndexToIns([2, 5, 10], 15) === 3);
|
||||
```
|
||||
|
||||
`getIndexToIns([2, 5, 10], 15)` should return a number.
|
||||
`getIndexToIns([2, 5, 10], 15)` 应返回一个数字。
|
||||
|
||||
```js
|
||||
assert(typeof getIndexToIns([2, 5, 10], 15) === 'number');
|
||||
```
|
||||
|
||||
`getIndexToIns([], 1)` should return `0`.
|
||||
`getIndexToIns([], 1)`应该返回 `0`。
|
||||
|
||||
```js
|
||||
assert(getIndexToIns([], 1) === 0);
|
||||
```
|
||||
|
||||
`getIndexToIns([], 1)` should return a number.
|
||||
`getIndexToIns([], 1)` 应返回一个数字。
|
||||
|
||||
```js
|
||||
assert(typeof getIndexToIns([], 1) === 'number');
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 587d7b7c367417b2b2512b1a
|
||||
title: Access Property Names with Bracket Notation
|
||||
title: 使用方括号访问属性名称
|
||||
challengeType: 1
|
||||
forumTopicId: 301150
|
||||
dashedName: access-property-names-with-bracket-notation
|
||||
@ -8,28 +8,28 @@ dashedName: access-property-names-with-bracket-notation
|
||||
|
||||
# --description--
|
||||
|
||||
In the first object challenge we mentioned the use of bracket notation as a way to access property values using the evaluation of a variable. For instance, imagine that our `foods` object is being used in a program for a supermarket cash register. We have some function that sets the `selectedFood` and we want to check our `foods` object for the presence of that food. This might look like:
|
||||
在关于对象的第一个挑战中，我们提到可以在一对方括号中用一个变量作为属性名来访问属性的值。 假设一个超市收银台程序中有一个 `foods` 对象, 并且有一个函数会设置 `selectedFood`；如果我们需要查询 `foods` 对象中，某种食物是否存在， 可以这样实现：
|
||||
|
||||
```js
|
||||
let selectedFood = getCurrentFood(scannedItem);
|
||||
let inventory = foods[selectedFood];
|
||||
```
|
||||
|
||||
This code will evaluate the value stored in the `selectedFood` variable and return the value of that key in the `foods` object, or `undefined` if it is not present. Bracket notation is very useful because sometimes object properties are not known before runtime or we need to access them in a more dynamic way.
|
||||
上述代码会先读取 `selectedFood` 变量的值，并返回 `foods` 对象中以该值命名的属性所对应的属性值。 若没有以该值命名的属性，则会返回 `undefined`。 有时候对象的属性名在运行之前是不确定的，或者我们需要动态地访问对象的属性值。在这些场景下，方括号表示法就变得十分有用。
|
||||
|
||||
# --instructions--
|
||||
|
||||
We've defined a function, `checkInventory`, which receives a scanned item as an argument. Return the current value of the `scannedItem` key in the `foods` object. You can assume that only valid keys will be provided as an argument to `checkInventory`.
|
||||
我们已经定义了 `checkInventory` 函数，它接受一个被扫描到的商品名作为输入参数。 请让这个函数返回 `foods` 对象中，以 `scannedItem` 的值所命名的属性对应的属性值。 在本挑战中，只有合理有效的属性名会作为参数传入 `checkInventory`，因此你不需要处理参数无效的情况。
|
||||
|
||||
# --hints--
|
||||
|
||||
`checkInventory` should be a function.
|
||||
`checkInventory` 应是一个函数。
|
||||
|
||||
```js
|
||||
assert.strictEqual(typeof checkInventory, 'function');
|
||||
```
|
||||
|
||||
The `foods` object should have only the following key-value pairs: `apples: 25`, `oranges: 32`, `plums: 28`, `bananas: 13`, `grapes: 35`, `strawberries: 27`.
|
||||
`foods` 对象应只包含以下键值对：`apples: 25`、`oranges: 32`、`plums: 28`、`bananas: 13`、`grapes: 35`、`strawberries: 27`。
|
||||
|
||||
```js
|
||||
assert.deepEqual(foods, {
|
||||
@ -42,19 +42,19 @@ assert.deepEqual(foods, {
|
||||
});
|
||||
```
|
||||
|
||||
`checkInventory("apples")` should return `25`.
|
||||
`checkInventory("apples")` 应返回 `25`。
|
||||
|
||||
```js
|
||||
assert.strictEqual(checkInventory('apples'), 25);
|
||||
```
|
||||
|
||||
`checkInventory("bananas")` should return `13`.
|
||||
`checkInventory("bananas")` 应返回 `13`。
|
||||
|
||||
```js
|
||||
assert.strictEqual(checkInventory('bananas'), 13);
|
||||
```
|
||||
|
||||
`checkInventory("strawberries")` should return `27`.
|
||||
`checkInventory("strawberries")` 应返回 `27`。
|
||||
|
||||
```js
|
||||
assert.strictEqual(checkInventory('strawberries'), 27);
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 587d7b7d367417b2b2512b1e
|
||||
title: Generate an Array of All Object Keys with Object.keys()
|
||||
title: 使用 Object.keys() 生成由对象的所有属性组成的数组
|
||||
challengeType: 1
|
||||
forumTopicId: 301160
|
||||
dashedName: generate-an-array-of-all-object-keys-with-object-keys
|
||||
@ -8,15 +8,15 @@ dashedName: generate-an-array-of-all-object-keys-with-object-keys
|
||||
|
||||
# --description--
|
||||
|
||||
We can also generate an array which contains all the keys stored in an object using the `Object.keys()` method and passing in an object as the argument. This will return an array with strings representing each property in the object. Again, there will be no specific order to the entries in the array.
|
||||
我们可以给 `Object.keys()` 方法传入一个对象作为参数，来生成包含对象所有键的数组。 这会返回一个由对象中所有属性（字符串）组成的数组。 需要注意的是，数组中元素的顺序是不确定的。
|
||||
|
||||
# --instructions--
|
||||
|
||||
Finish writing the `getArrayOfUsers` function so that it returns an array containing all the properties in the object it receives as an argument.
|
||||
请完成 `getArrayOfUsers` 函数的实现，使其返回一个由输入对象中的所有属性所组成的数组。
|
||||
|
||||
# --hints--
|
||||
|
||||
The `users` object should only contain the keys `Alan`, `Jeff`, `Sarah`, and `Ryan`
|
||||
`users` 对象应该只包含 `Alan`、`Jeff`、`Sarah`、`Ryan` 这 4 个属性。
|
||||
|
||||
```js
|
||||
assert(
|
||||
@ -28,7 +28,7 @@ assert(
|
||||
);
|
||||
```
|
||||
|
||||
The `getArrayOfUsers` function should return an array which contains all the keys in the `users` object
|
||||
`getArrayOfUsers` 函数应返回一个包含 `users` 对象中所有属性的数组。
|
||||
|
||||
```js
|
||||
assert(
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 587d7b7d367417b2b2512b1f
|
||||
title: Modify an Array Stored in an Object
|
||||
title: 修改存储在对象中的数组
|
||||
challengeType: 1
|
||||
forumTopicId: 301163
|
||||
dashedName: modify-an-array-stored-in-an-object
|
||||
@ -8,21 +8,21 @@ dashedName: modify-an-array-stored-in-an-object
|
||||
|
||||
# --description--
|
||||
|
||||
Now you've seen all the basic operations for JavaScript objects. You can add, modify, and remove key-value pairs, check if keys exist, and iterate over all the keys in an object. As you continue learning JavaScript you will see even more versatile applications of objects. Additionally, the Data Structures lessons located in the Coding Interview Prep section of the curriculum also cover the ES6 <dfn>Map</dfn> and <dfn>Set</dfn> objects, both of which are similar to ordinary objects but provide some additional features. Now that you've learned the basics of arrays and objects, you're fully prepared to begin tackling more complex problems using JavaScript!
|
||||
我们已经学习了 JavaScript 对象的这些基本操作： 添加、修改、移除键值对、检查某个属性是否存在、遍历对象的所有属性。 在继续学习 JavaScript 的过程中，我们会了解对象的更多用法。 另外，在之后的数据结构课程中，我们还会学习 ES6 的 <dfn>Map</dfn> 和 <dfn>Set</dfn>。 这两种数据结构与我们现在学到的对象十分类似，但它们在对象的基础上提供了一些额外的功能。 目前，我们已经学习了数组和对象的基础知识，让我们试着来用所学的知识解决一些更复杂的问题。
|
||||
|
||||
# --instructions--
|
||||
|
||||
Take a look at the object we've provided in the code editor. The `user` object contains three keys. The `data` key contains five keys, one of which contains an array of `friends`. From this, you can see how flexible objects are as data structures. We've started writing a function `addFriend`. Finish writing it so that it takes a `user` object and adds the name of the `friend` argument to the array stored in `user.data.friends` and returns that array.
|
||||
请看一下代码编辑器中我们为你写好的对象。 `user` 对象包含 3 个属性； `data` 对象包含 5 个属性，其中包含一个叫做 `friends` 的数组。 这就是对象作为数据结构所展现出的灵活性。 我们已经写好了 `addFriend` 函数的一部分， 请你完成这个函数，使其接受一个 `user` 对象，将 `friend` 参数中的名字添加到 `user.data.friends` 数组中并返回该数组。
|
||||
|
||||
# --hints--
|
||||
|
||||
The `user` object should have `name`, `age`, and `data` keys.
|
||||
`user` 对象应该包含 `name`、`age` 和 `data` 三个属性。
|
||||
|
||||
```js
|
||||
assert('name' in user && 'age' in user && 'data' in user);
|
||||
```
|
||||
|
||||
The `addFriend` function should accept a `user` object and a `friend` string as arguments and add the friend to the array of `friends` in the `user` object.
|
||||
`addFriend` 函数应该接受一个 `user` 对象和一个 `friend` 字符串作为输入参数，并将这个字符串插入到 `user` 对象的 `friends` 数组中。
|
||||
|
||||
```js
|
||||
assert(
|
||||
@ -35,7 +35,7 @@ assert(
|
||||
);
|
||||
```
|
||||
|
||||
`addFriend(user, "Pete")` should return `["Sam", "Kira", "Tomo", "Pete"]`.
|
||||
`addFriend(user, "Pete")` 应该返回 `["Sam", "Kira", "Tomo", "Pete"]`。
|
||||
|
||||
```js
|
||||
assert.deepEqual(
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 587d7b7c367417b2b2512b19
|
||||
title: Modify an Object Nested Within an Object
|
||||
title: 修改嵌套在对象中的对象
|
||||
challengeType: 1
|
||||
forumTopicId: 301164
|
||||
dashedName: modify-an-object-nested-within-an-object
|
||||
@ -8,7 +8,7 @@ dashedName: modify-an-object-nested-within-an-object
|
||||
|
||||
# --description--
|
||||
|
||||
Now let's take a look at a slightly more complex object. Object properties can be nested to an arbitrary depth, and their values can be any type of data supported by JavaScript, including arrays and even other objects. Consider the following:
|
||||
现在我们来看一个稍复杂的对象。 在对象中，我们也可以嵌套任意层数的对象，对象的属性值可以是 JavaScript 支持的任意类型，包括数组和其他对象。 请看以下例子：
|
||||
|
||||
```js
|
||||
let nestedObject = {
|
||||
@ -26,7 +26,7 @@ let nestedObject = {
|
||||
};
|
||||
```
|
||||
|
||||
`nestedObject` has three properties: `id` (value is a number), `date` (value is a string), and `data` (value is an object with its nested structure). While structures can quickly become complex, we can still use the same notations to access the information we need. To assign the value `10` to the `busy` property of the nested `onlineStatus` object, we use dot notation to reference the property:
|
||||
`nestedObject` 有 3 个属性：`id`（属性值为数字）、`date`（属性值为字符串）、`data`（属性值为嵌套的对象）。 虽然对象中的数据可能很复杂，我们仍能使用上一个挑战中讲到的写法来访问我们需要的信息。 如果我们想把嵌套在 `onlineStatus` 中 `busy` 的属性值改为 `10`，可以用点号表示法来这样实现：
|
||||
|
||||
```js
|
||||
nestedObject.data.onlineStatus.busy = 10;
|
||||
@ -34,11 +34,11 @@ nestedObject.data.onlineStatus.busy = 10;
|
||||
|
||||
# --instructions--
|
||||
|
||||
Here we've defined an object `userActivity`, which includes another object nested within it. Set the value of the `online` key to `45`.
|
||||
我们已经定义了一个 `userActivity` 对象，它包含了另一个对象。 请将 `online` 的属性值改为 `45`。
|
||||
|
||||
# --hints--
|
||||
|
||||
`userActivity` should have `id`, `date` and `data` properties.
|
||||
`userActivity` 应包含 `id`、`date` 和 `data` 属性。
|
||||
|
||||
```js
|
||||
assert(
|
||||
@ -46,19 +46,19 @@ assert(
|
||||
);
|
||||
```
|
||||
|
||||
`userActivity` should have a `data` key set to an object with keys `totalUsers` and `online`.
|
||||
`userActivity` 应包含 `data` 属性，其属性值应为包含 `totalUsers` 和 `online` 属性的对象。
|
||||
|
||||
```js
|
||||
assert('totalUsers' in userActivity.data && 'online' in userActivity.data);
|
||||
```
|
||||
|
||||
The `online` property nested in the `data` key of `userActivity` should be set to `45`
|
||||
`userActivity` 的 `data` 属性值中的 `online` 属性值应被改为 `45`。
|
||||
|
||||
```js
|
||||
assert(userActivity.data.online === 45);
|
||||
```
|
||||
|
||||
The `online` property should be set using dot or bracket notation.
|
||||
应使用点号表示法或方括号表示法来修改 `online` 属性值。
|
||||
|
||||
```js
|
||||
assert.strictEqual(code.search(/online: 45/), -1);
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 587d7b7c367417b2b2512b1b
|
||||
title: Use the delete Keyword to Remove Object Properties
|
||||
title: 使用 delete 关键字删除对象属性
|
||||
challengeType: 1
|
||||
forumTopicId: 301168
|
||||
dashedName: use-the-delete-keyword-to-remove-object-properties
|
||||
@ -8,11 +8,11 @@ dashedName: use-the-delete-keyword-to-remove-object-properties
|
||||
|
||||
# --description--
|
||||
|
||||
Now you know what objects are and their basic features and advantages. In short, they are key-value stores which provide a flexible, intuitive way to structure data, ***and***, they provide very fast lookup time. Throughout the rest of these challenges, we will describe several common operations you can perform on objects so you can become comfortable applying these useful data structures in your programs.
|
||||
现在我们已经学习了什么是对象以及对象的基本特性和用途。 总之，对象是以键值对的形式，灵活、直观地存储结构化数据的一种方式，***而且***，通过对象的属性查找属性值是速度很快的操作。 在本章余下的挑战中，我们来了解一下对象的几种常用操作，这样你能更好地在代码中使用这个十分有用的数据结构：对象。
|
||||
|
||||
In earlier challenges, we have both added to and modified an object's key-value pairs. Here we will see how we can *remove* a key-value pair from an object.
|
||||
在之前的挑战中，我们已经试过添加和修改对象中的键值对。 现在我们来看看如何从一个对象中*移除*一个键值对。
|
||||
|
||||
Let's revisit our `foods` object example one last time. If we wanted to remove the `apples` key, we can remove it by using the `delete` keyword like this:
|
||||
我们再来回顾一下上一个挑战中的 `foods` 对象。 如果我们想移除 `apples` 属性，可以像这样使用 `delete` 关键字：
|
||||
|
||||
```js
|
||||
delete foods.apples;
|
||||
@ -20,11 +20,11 @@ delete foods.apples;
|
||||
|
||||
# --instructions--
|
||||
|
||||
Use the delete keyword to remove the `oranges`, `plums`, and `strawberries` keys from the `foods` object.
|
||||
请使用 delete 关键字来移除 `foods` 中的 `oranges`、`plums` 和 `strawberries` 属性。
|
||||
|
||||
# --hints--
|
||||
|
||||
The `foods` object should only have three keys: `apples`, `grapes`, and `bananas`.
|
||||
`foods` 对象应只包含 3 个属性：`apples`、`grapes` 和 `bananas`。
|
||||
|
||||
```js
|
||||
assert(
|
||||
@ -35,7 +35,7 @@ assert(
|
||||
);
|
||||
```
|
||||
|
||||
The `oranges`, `plums`, and `strawberries` keys should be removed using `delete`.
|
||||
应使用 `delete` 关键字来移除 `oranges`、`plums` 和 `strawberries` 属性。
|
||||
|
||||
```js
|
||||
assert(
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 56533eb9ac21ba0edf2244c3
|
||||
title: Assignment with a Returned Value
|
||||
title: 使用返回值赋值
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/ce2pEtB'
|
||||
forumTopicId: 16658
|
||||
@ -9,27 +9,27 @@ dashedName: assignment-with-a-returned-value
|
||||
|
||||
# --description--
|
||||
|
||||
If you'll recall from our discussion of [Storing Values with the Assignment Operator](/learn/javascript-algorithms-and-data-structures/basic-javascript/storing-values-with-the-assignment-operator), everything to the right of the equal sign is resolved before the value is assigned. This means we can take the return value of a function and assign it to a variable.
|
||||
如果你还记得我们在[使用赋值运算符存储值](/learn/javascript-algorithms-and-data-structures/basic-javascript/storing-values-with-the-assignment-operator)中的讨论的话，等号右侧的所有操作都会在赋值之前完成。 这意味着我们可以获取函数的返回值，并将其赋值给一个变量。
|
||||
|
||||
Assume we have pre-defined a function `sum` which adds two numbers together, then:
|
||||
假设我们有一个预先定义的函数 `sum` ，它将两个数相加，然后：
|
||||
|
||||
`ourSum = sum(5, 12);`
|
||||
|
||||
will call `sum` function, which returns a value of `17` and assigns it to `ourSum` variable.
|
||||
将会调用函数 `sum`，函数返回值 `17`，然后将该值赋给变量 `ourSum`。
|
||||
|
||||
# --instructions--
|
||||
|
||||
Call the `processArg` function with an argument of `7` and assign its return value to the variable `processed`.
|
||||
调用函数 `processArg`，传入参数 `7`，并将它的返回值赋给变量 `processed`。
|
||||
|
||||
# --hints--
|
||||
|
||||
`processed` should have a value of `2`
|
||||
`processed` 的值应为 `2`。
|
||||
|
||||
```js
|
||||
assert(processed === 2);
|
||||
```
|
||||
|
||||
You should assign `processArg` to `processed`
|
||||
你应该将 `processArg` 赋值给 `processed`。
|
||||
|
||||
```js
|
||||
assert(/processed\s*=\s*processArg\(\s*7\s*\)/.test(code));
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 56533eb9ac21ba0edf2244b2
|
||||
title: Compound Assignment With Augmented Division
|
||||
title: 复合赋值之 /=
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/c2QvKT2'
|
||||
forumTopicId: 16659
|
||||
@ -9,45 +9,45 @@ dashedName: compound-assignment-with-augmented-division
|
||||
|
||||
# --description--
|
||||
|
||||
The `/=` operator divides a variable by another number.
|
||||
`/=` 操作符是让变量与另一个数相除并赋值。
|
||||
|
||||
`myVar = myVar / 5;`
|
||||
|
||||
Will divide `myVar` by `5`. This can be rewritten as:
|
||||
变量 `myVar` 等于自身除以 `5` 的值。 等价于:
|
||||
|
||||
`myVar /= 5;`
|
||||
|
||||
# --instructions--
|
||||
|
||||
Convert the assignments for `a`, `b`, and `c` to use the `/=` operator.
|
||||
使用 `/=` 操作符对 `a`，`b` 和 `c` 实现相除赋值操作。
|
||||
|
||||
# --hints--
|
||||
|
||||
`a` should equal `4`.
|
||||
`a` 应该等于 `4`。
|
||||
|
||||
```js
|
||||
assert(a === 4);
|
||||
```
|
||||
|
||||
`b` should equal `27`.
|
||||
`b` 应该等于 `27`。
|
||||
|
||||
```js
|
||||
assert(b === 27);
|
||||
```
|
||||
|
||||
`c` should equal `3`.
|
||||
`c` 应该等于`3`。
|
||||
|
||||
```js
|
||||
assert(c === 3);
|
||||
```
|
||||
|
||||
You should use the `/=` operator for each variable.
|
||||
应该对每个变量使用 `/=` 操作符。
|
||||
|
||||
```js
|
||||
assert(code.match(/\/=/g).length === 3);
|
||||
```
|
||||
|
||||
You should not modify the code above the specified comment.
|
||||
不要修改注释上面的代码。
|
||||
|
||||
```js
|
||||
assert(
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 56533eb9ac21ba0edf2244b1
|
||||
title: Compound Assignment With Augmented Multiplication
|
||||
title: 复合赋值之 *=
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/c83vrfa'
|
||||
forumTopicId: 16662
|
||||
@ -9,45 +9,45 @@ dashedName: compound-assignment-with-augmented-multiplication
|
||||
|
||||
# --description--
|
||||
|
||||
The `*=` operator multiplies a variable by a number.
|
||||
`*=` 操作符是让变量与一个数相乘并赋值。
|
||||
|
||||
`myVar = myVar * 5;`
|
||||
|
||||
will multiply `myVar` by `5`. This can be rewritten as:
|
||||
变量 `myVar` 等于自身与数值 `5` 相乘的值。 也可以写作这样的形式:
|
||||
|
||||
`myVar *= 5;`
|
||||
|
||||
# --instructions--
|
||||
|
||||
Convert the assignments for `a`, `b`, and `c` to use the `*=` operator.
|
||||
使用 `*=` 操作符给 `a`，`b` 和 `c` 实现赋值相乘操作。
|
||||
|
||||
# --hints--
|
||||
|
||||
`a` should equal `25`.
|
||||
`a` 应该等于`25`。
|
||||
|
||||
```js
|
||||
assert(a === 25);
|
||||
```
|
||||
|
||||
`b` should equal `36`.
|
||||
`b` 应该等于`36`。
|
||||
|
||||
```js
|
||||
assert(b === 36);
|
||||
```
|
||||
|
||||
`c` should equal `46`.
|
||||
`c` 应该等于`46`。
|
||||
|
||||
```js
|
||||
assert(c === 46);
|
||||
```
|
||||
|
||||
You should use the `*=` operator for each variable.
|
||||
应该对每个变量使用 `*=` 操作符。
|
||||
|
||||
```js
|
||||
assert(code.match(/\*=/g).length === 3);
|
||||
```
|
||||
|
||||
You should not modify the code above the specified comment.
|
||||
不要修改注释上面的代码。
|
||||
|
||||
```js
|
||||
assert(
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 56533eb9ac21ba0edf2244b0
|
||||
title: Compound Assignment With Augmented Subtraction
|
||||
title: 复合赋值之 -=
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/c2Qv7AV'
|
||||
forumTopicId: 16660
|
||||
@ -9,45 +9,45 @@ dashedName: compound-assignment-with-augmented-subtraction
|
||||
|
||||
# --description--
|
||||
|
||||
Like the `+=` operator, `-=` subtracts a number from a variable.
|
||||
与 `+=` 操作符类似，`-=` 操作符用来对一个变量进行减法赋值操作。
|
||||
|
||||
`myVar = myVar - 5;`
|
||||
|
||||
will subtract `5` from `myVar`. This can be rewritten as:
|
||||
变量 `myVar` 等于自身减去 `5` 的值。 也可以写成这种形式：
|
||||
|
||||
`myVar -= 5;`
|
||||
|
||||
# --instructions--
|
||||
|
||||
Convert the assignments for `a`, `b`, and `c` to use the `-=` operator.
|
||||
使用 `-=` 操作符对 `a`，`b` 和 `c` 实现相减赋值。
|
||||
|
||||
# --hints--
|
||||
|
||||
`a` should equal `5`.
|
||||
`a` 应该等于 `5`。
|
||||
|
||||
```js
|
||||
assert(a === 5);
|
||||
```
|
||||
|
||||
`b` should equal `-6`.
|
||||
`b` 应该等于 `-6`。
|
||||
|
||||
```js
|
||||
assert(b === -6);
|
||||
```
|
||||
|
||||
`c` should equal `2`.
|
||||
`c` 应该等于 `2`。
|
||||
|
||||
```js
|
||||
assert(c === 2);
|
||||
```
|
||||
|
||||
You should use the `-=` operator for each variable.
|
||||
应该对每个变量使用 `-=` 操作符。
|
||||
|
||||
```js
|
||||
assert(code.match(/-=/g).length === 3);
|
||||
```
|
||||
|
||||
You should not modify the code above the specified comment.
|
||||
不要修改注释上面的代码。
|
||||
|
||||
```js
|
||||
assert(
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: bd7123c9c443eddfaeb5bdef
|
||||
title: Declare JavaScript Variables
|
||||
title: 声明变量
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/cNanrHq'
|
||||
forumTopicId: 17556
|
||||
@ -9,32 +9,32 @@ dashedName: declare-javascript-variables
|
||||
|
||||
# --description--
|
||||
|
||||
In computer science, <dfn>data</dfn> is anything that is meaningful to the computer. JavaScript provides eight different <dfn>data types</dfn> which are `undefined`, `null`, `boolean`, `string`, `symbol`, `bigint`, `number`, and `object`.
|
||||
在计算机科学中，<dfn>数据</dfn>就是一切，它对于计算机意义重大。 JavaScript 提供七种不同的<dfn>数据类型</dfn>，它们是 `undefined`（未定义）、`null`（空）、`boolean`（布尔型）、`string`（字符串）、`symbol`、`number`（数字）、`bigint`（可以表示任意大的整数）和 `object`（对象）。
|
||||
|
||||
For example, computers distinguish between numbers, such as the number `12`, and `strings`, such as `"12"`, `"dog"`, or `"123 cats"`, which are collections of characters. Computers can perform mathematical operations on a number, but not on a string.
|
||||
例如，计算机区分数字，例如 `12`，和由字符组成的字符串 `strings`，例如 `"12"`、`"dog"` 或 `"123 cats"`。 计算机可以对数字执行数学运算，但不能对字符串执行数学运算。
|
||||
|
||||
<dfn>Variables</dfn> allow computers to store and manipulate data in a dynamic fashion. They do this by using a "label" to point to the data rather than using the data itself. Any of the eight data types may be stored in a variable.
|
||||
<dfn>变量</dfn>允许计算机以一种动态的形式来存储和操作数据， 即通过操作指向数据的指针而不是数据本身来实现。 以上八种数据类型中的任何一种都可以存储到一个变量中。
|
||||
|
||||
`Variables` are similar to the x and y variables you use in mathematics, which means they're a simple name to represent the data we want to refer to. Computer `variables` differ from mathematical variables in that they can store different values at different times.
|
||||
变量非常类似于你在数学中使用的 x、y 变量，都是以一个简单命名的名称来代替我们赋值给它的数据。 计算机中的变量与数学中的变量不同的是，计算机可以在不同的时间存储不同类型的变量。
|
||||
|
||||
We tell JavaScript to create or <dfn>declare</dfn> a variable by putting the keyword `var` in front of it, like so:
|
||||
通过在变量前面使用关键字 `var`，<dfn>声明</dfn>一个变量，例如：
|
||||
|
||||
```js
|
||||
var ourName;
|
||||
```
|
||||
|
||||
creates a `variable` called `ourName`. In JavaScript we end statements with semicolons. `Variable` names can be made up of numbers, letters, and `$` or `_`, but may not contain spaces or start with a number.
|
||||
上面代码的意思是创建一个名为 `ourName` 的变量。 在 JavaScript 中我们以分号结束语句。 变量名称可以由数字、字母、美元符号 `$` 或者下划线 `_` 组成，但是不能包含空格或者以数字为开头。
|
||||
|
||||
# --instructions--
|
||||
|
||||
Use the `var` keyword to create a variable called `myName`.
|
||||
使用 `var` 关键字来创建一个名为 `myName` 的变量。
|
||||
|
||||
**Hint**
|
||||
Look at the `ourName` example above if you get stuck.
|
||||
**提示：**
|
||||
如果遇到困难了，请看下 `ourName` 的例子是怎么写的。
|
||||
|
||||
# --hints--
|
||||
|
||||
You should declare `myName` with the `var` keyword, ending with a semicolon
|
||||
使用 `var` 关键字定义一个变量 `myName`，并使用分号结尾。
|
||||
|
||||
```js
|
||||
assert(/var\s+myName\s*;/.test(code));
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: bd7993c9ca9feddfaeb7bdef
|
||||
title: Divide One Decimal by Another with JavaScript
|
||||
title: 两个小数相除
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/cBZe9AW'
|
||||
forumTopicId: 18255
|
||||
@ -9,27 +9,27 @@ dashedName: divide-one-decimal-by-another-with-javascript
|
||||
|
||||
# --description--
|
||||
|
||||
Now let's divide one decimal by another.
|
||||
现在让我们将一个小数除以另一个小数。
|
||||
|
||||
# --instructions--
|
||||
|
||||
Change the `0.0` so that `quotient` will equal to `2.2`.
|
||||
改变数值 `0.0` 的值让变量 `quotient` 的值等于 `2.2`。
|
||||
|
||||
# --hints--
|
||||
|
||||
The variable `quotient` should equal `2.2`
|
||||
`quotient` 的值应该等于`2.2`。
|
||||
|
||||
```js
|
||||
assert(quotient === 2.2);
|
||||
```
|
||||
|
||||
You should use the `/` operator to divide 4.4 by 2
|
||||
使用 `/` 运算符将 4.4 除以 2。
|
||||
|
||||
```js
|
||||
assert(/4\.40*\s*\/\s*2\.*0*/.test(code));
|
||||
```
|
||||
|
||||
The quotient variable should only be assigned once
|
||||
quotient 变量应该只被赋值一次。
|
||||
|
||||
```js
|
||||
assert(code.match(/quotient/g).length === 1);
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 56533eb9ac21ba0edf2244b5
|
||||
title: Escaping Literal Quotes in Strings
|
||||
title: 转义字符串中的引号
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/c2QvgSr'
|
||||
forumTopicId: 17568
|
||||
@ -9,31 +9,31 @@ dashedName: escaping-literal-quotes-in-strings
|
||||
|
||||
# --description--
|
||||
|
||||
When you are defining a string you must start and end with a single or double quote. What happens when you need a literal quote: `"` or `'` inside of your string?
|
||||
定义一个字符串必须要用单引号或双引号来包裹它。 那么当你的字符串里面包含引号 `"` 或者 `'` 时该怎么办呢?
|
||||
|
||||
In JavaScript, you can <dfn>escape</dfn> a quote from considering it as an end of string quote by placing a <dfn>backslash</dfn> (<code>\\</code>) in front of the quote.
|
||||
在 JavaScript 中，你可以通过在引号前面使用<dfn>反斜杠</dfn>（<code>\\</code>）来<dfn>转义</dfn>引号。
|
||||
|
||||
`var sampleStr = "Alan said, \"Peter is learning JavaScript\".";`
|
||||
|
||||
This signals to JavaScript that the following quote is not the end of the string, but should instead appear inside the string. So if you were to print this to the console, you would get:
|
||||
有了转义符号，JavaScript 就知道这个单引号或双引号并不是字符串的结尾，而是字符串内的字符。 所以，上面的字符串打印到控制台的结果为：
|
||||
|
||||
`Alan said, "Peter is learning JavaScript".`
|
||||
|
||||
# --instructions--
|
||||
|
||||
Use <dfn>backslashes</dfn> to assign a string to the `myStr` variable so that if you were to print it to the console, you would see:
|
||||
使用<dfn>反斜杠</dfn>将一个字符串赋值给变量 `myStr`，打印到控制台，输出为：
|
||||
|
||||
`I am a "double quoted" string inside "double quotes".`
|
||||
|
||||
# --hints--
|
||||
|
||||
You should use two double quotes (`"`) and four escaped double quotes (`\"`).
|
||||
你的代码中应该包含两个双引号（`"`）以及四个转义的双引号（`\"`）。
|
||||
|
||||
```js
|
||||
assert(code.match(/\\"/g).length === 4 && code.match(/[^\\]"/g).length === 2);
|
||||
```
|
||||
|
||||
Variable myStr should contain the string: `I am a "double quoted" string inside "double quotes".`
|
||||
变量 myStr 应该包含字符串 `I am a "double quoted" string inside "double quotes".`。
|
||||
|
||||
```js
|
||||
assert(/I am a "double quoted" string inside "double quotes(\."|"\.)$/.test(myStr));
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: cf1111c1c12feddfaeb1bdef
|
||||
title: Generate Random Whole Numbers with JavaScript
|
||||
title: 使用 JavaScript 生成随机整数
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/cRn6bfr'
|
||||
forumTopicId: 18186
|
||||
@ -9,25 +9,25 @@ dashedName: generate-random-whole-numbers-with-javascript
|
||||
|
||||
# --description--
|
||||
|
||||
It's great that we can generate random decimal numbers, but it's even more useful if we use it to generate random whole numbers.
|
||||
生成随机小数很棒，但随机数更有用的地方在于生成随机整数。
|
||||
|
||||
<ol><li>Use <code>Math.random()</code> to generate a random decimal.</li><li>Multiply that random decimal by <code>20</code>.</li><li>Use another function, <code>Math.floor()</code> to round the number down to its nearest whole number.</li></ol>
|
||||
<ol><li>用 <code>Math.random()</code> 生成一个随机小数。</li><li>把这个随机小数乘以 <code>20</code>。</li><li>用 <code>Math.floor()</code> 向下取整，获得它最近的整数。</li></ol>
|
||||
|
||||
Remember that `Math.random()` can never quite return a `1` and, because we're rounding down, it's impossible to actually get `20`. This technique will give us a whole number between `0` and `19`.
|
||||
记住 `Math.random()` 永远不会返回 `1`。同时因为我们是在向下取整，所以最终我们获得的结果不可能有 `20`。 这确保了我们获得了一个在 `0` 到 `19` 之间的整数。
|
||||
|
||||
Putting everything together, this is what our code looks like:
|
||||
把操作连缀起来，代码类似于下面：
|
||||
|
||||
`Math.floor(Math.random() * 20);`
|
||||
|
||||
We are calling `Math.random()`, multiplying the result by 20, then passing the value to `Math.floor()` function to round the value down to the nearest whole number.
|
||||
我们先调用 `Math.random()`，把它的结果乘以 20，然后把上一步的结果传给 `Math.floor()`，最终通过向下取整获得最近的整数。
|
||||
|
||||
# --instructions--
|
||||
|
||||
Use this technique to generate and return a random whole number between `0` and `9`.
|
||||
生成一个 `0` 到 `9` 之间的随机整数。
|
||||
|
||||
# --hints--
|
||||
|
||||
The result of `randomWholeNum` should be a whole number.
|
||||
`randomWholeNum` 的结果应该是一个整数。
|
||||
|
||||
```js
|
||||
assert(
|
||||
@ -39,13 +39,13 @@ assert(
|
||||
);
|
||||
```
|
||||
|
||||
You should use `Math.random` to generate a random number.
|
||||
需要使用 `Math.random` 生成一个随机数字。
|
||||
|
||||
```js
|
||||
assert(code.match(/Math.random/g).length >= 1);
|
||||
```
|
||||
|
||||
You should have multiplied the result of `Math.random` by 10 to make it a number that is between zero and nine.
|
||||
应该将 `Math.random` 的结果乘以 10，以生成 0 到 9 之间的随机数。
|
||||
|
||||
```js
|
||||
assert(
|
||||
@ -54,7 +54,7 @@ assert(
|
||||
);
|
||||
```
|
||||
|
||||
You should use `Math.floor` to remove the decimal part of the number.
|
||||
需要使用 `Math.floor` 移除数字中的小数部分。
|
||||
|
||||
```js
|
||||
assert(code.match(/Math.floor/g).length >= 1);
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: cf1111c1c12feddfaeb2bdef
|
||||
title: Generate Random Whole Numbers within a Range
|
||||
title: 生成某个范围内的随机整数
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/cm83yu6'
|
||||
forumTopicId: 18187
|
||||
@ -9,39 +9,39 @@ dashedName: generate-random-whole-numbers-within-a-range
|
||||
|
||||
# --description--
|
||||
|
||||
Instead of generating a random whole number between zero and a given number like we did before, we can generate a random whole number that falls within a range of two specific numbers.
|
||||
我们之前生成的随机数是在 0 到某个数之间，现在我们要生成的随机数是在两个指定的数之间。
|
||||
|
||||
To do this, we'll define a minimum number `min` and a maximum number `max`.
|
||||
我们需要定义一个最小值 `min` 和一个最大值 `max`。
|
||||
|
||||
Here's the formula we'll use. Take a moment to read it and try to understand what this code is doing:
|
||||
下面是我们将要使用的方法， 仔细看看并尝试理解这行代码到底在干嘛：
|
||||
|
||||
`Math.floor(Math.random() * (max - min + 1)) + min`
|
||||
|
||||
# --instructions--
|
||||
|
||||
Create a function called `randomRange` that takes a range `myMin` and `myMax` and returns a random whole number that's greater than or equal to `myMin`, and is less than or equal to `myMax`, inclusive.
|
||||
创建一个函数 `randomRange`，接收参数的范围在 `myMin` 和 `myMax`之间，返回一个在 `myMin`（包括 myMin）和 `myMax`（包括 myMax）之间的随机整数。
|
||||
|
||||
# --hints--
|
||||
|
||||
The lowest random number that can be generated by `randomRange` should be equal to your minimum number, `myMin`.
|
||||
`randomRange` 返回的随机数应该大于或等于 `myMin`。
|
||||
|
||||
```js
|
||||
assert(calcMin === 5);
|
||||
```
|
||||
|
||||
The highest random number that can be generated by `randomRange` should be equal to your maximum number, `myMax`.
|
||||
`randomRange` 返回的随机数最大值应该等于 `myMax`。
|
||||
|
||||
```js
|
||||
assert(calcMax === 15);
|
||||
```
|
||||
|
||||
The random number generated by `randomRange` should be an integer, not a decimal.
|
||||
`randomRange` 应该返回一个随机整数，而不是小数。
|
||||
|
||||
```js
|
||||
assert(randomRange(0, 1) % 1 === 0);
|
||||
```
|
||||
|
||||
`randomRange` should use both `myMax` and `myMin`, and return a random number in your range.
|
||||
`randomRange` 应该使用 `myMax` 和 `myMin`，并且返回两者之间的随机数。
|
||||
|
||||
```js
|
||||
assert(
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 56533eb9ac21ba0edf2244be
|
||||
title: Global Scope and Functions
|
||||
title: 全局作用域和函数
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/cQM7mCN'
|
||||
forumTopicId: 18193
|
||||
@ -9,37 +9,37 @@ dashedName: global-scope-and-functions
|
||||
|
||||
# --description--
|
||||
|
||||
In JavaScript, <dfn>scope</dfn> refers to the visibility of variables. Variables which are defined outside of a function block have <dfn>Global</dfn> scope. This means, they can be seen everywhere in your JavaScript code.
|
||||
在 JavaScript 中，<dfn>作用域</dfn>涉及到变量的作用范围。 在函数外定义的变量具有 <dfn>全局</dfn> 作用域。 这意味着，具有全局作用域的变量可以在代码的任何地方被调用。
|
||||
|
||||
Variables which are used without the `var` keyword are automatically created in the `global` scope. This can create unintended consequences elsewhere in your code or when running a function again. You should always declare your variables with `var`.
|
||||
这些没有使用 `var` 关键字定义的变量，会被自动创建在 `global` 作用域中，形成全局变量。 当在代码其他地方无意间定义了一个变量，刚好变量名与全局变量相同，这时会产生意想不到的后果。 因此你应该总是使用 `var` 关键字来声明你的变量。
|
||||
|
||||
# --instructions--
|
||||
|
||||
Using `var`, declare a global variable named `myGlobal` outside of any function. Initialize it with a value of `10`.
|
||||
使用 `var`，在函数外声明一个全局变量 `myGlobal`， 并给它一个初始值 `10`。
|
||||
|
||||
Inside function `fun1`, assign `5` to `oopsGlobal` ***without*** using the `var` keyword.
|
||||
在函数 `fun1` 的内部，***不***使用 `var` 关键字，声明 `oopsGlobal`，并给它赋值为 `5`。
|
||||
|
||||
# --hints--
|
||||
|
||||
`myGlobal` should be defined
|
||||
应定义 `myGlobal`。
|
||||
|
||||
```js
|
||||
assert(typeof myGlobal != 'undefined');
|
||||
```
|
||||
|
||||
`myGlobal` should have a value of `10`
|
||||
`myGlobal` 的值应为 `10`。
|
||||
|
||||
```js
|
||||
assert(myGlobal === 10);
|
||||
```
|
||||
|
||||
`myGlobal` should be declared using the `var` keyword
|
||||
应使用 `var` 关键字定义 `myGlobal`。
|
||||
|
||||
```js
|
||||
assert(/var\s+myGlobal/.test(code));
|
||||
```
|
||||
|
||||
`oopsGlobal` should be a global variable and have a value of `5`
|
||||
`oopsGlobal` 应为全局变量，值为 `5`。
|
||||
|
||||
```js
|
||||
assert(typeof oopsGlobal != 'undefined' && oopsGlobal === 5);
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 56533eb9ac21ba0edf2244a9
|
||||
title: Initializing Variables with the Assignment Operator
|
||||
title: 使用赋值运算符初始化变量
|
||||
challengeType: 1
|
||||
videoUrl: 'https://scrimba.com/c/cWJ4Bfb'
|
||||
forumTopicId: 301171
|
||||
@ -9,19 +9,19 @@ dashedName: initializing-variables-with-the-assignment-operator
|
||||
|
||||
# --description--
|
||||
|
||||
It is common to <dfn>initialize</dfn> a variable to an initial value in the same line as it is declared.
|
||||
通常在声明变量的时候会给变量<dfn>初始化</dfn>一个初始值。
|
||||
|
||||
`var myVar = 0;`
|
||||
|
||||
Creates a new variable called `myVar` and assigns it an initial value of `0`.
|
||||
创建一个名为 `myVar` 的变量，并指定其初始值 `0`。
|
||||
|
||||
# --instructions--
|
||||
|
||||
Define a variable `a` with `var` and initialize it to a value of `9`.
|
||||
通过关键字 `var` 定义一个变量 `a`，并给它一个初始值 `9`。
|
||||
|
||||
# --hints--
|
||||
|
||||
You should initialize `a` to a value of `9`.
|
||||
你需要初始化 `a` 的值为 `9`。
|
||||
|
||||
```js
|
||||
assert(/var\s+a\s*=\s*9(\s*;?\s*)$/.test(code));
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 587d7b85367417b2b2512b3a
|
||||
title: Catch Arguments Passed in the Wrong Order When Calling a Function
|
||||
title: 调用函数时，捕获以错误顺序传递的参数
|
||||
challengeType: 1
|
||||
forumTopicId: 301184
|
||||
dashedName: catch-arguments-passed-in-the-wrong-order-when-calling-a-function
|
||||
@ -8,21 +8,21 @@ dashedName: catch-arguments-passed-in-the-wrong-order-when-calling-a-function
|
||||
|
||||
# --description--
|
||||
|
||||
Continuing the discussion on calling functions, the next bug to watch out for is when a function's arguments are supplied in the incorrect order. If the arguments are different types, such as a function expecting an array and an integer, this will likely throw a runtime error. If the arguments are the same type (all integers, for example), then the logic of the code won't make sense. Make sure to supply all required arguments, in the proper order to avoid these issues.
|
||||
继续讨论调用函数，需要注意的下一个 bug 是函数的参数传递顺序错误。 如果参数分别是不同的类型，例如接受数组和整数两个参数的函数，参数顺序传错就可能会引发运行时错误。 对于接受相同类型参数的函数，传错参数也会导致逻辑错误或运行结果错误。 确保以正确的顺序提供所有必需的参数以避免这些问题。
|
||||
|
||||
# --instructions--
|
||||
|
||||
The function `raiseToPower` raises a base to an exponent. Unfortunately, it's not called properly - fix the code so the value of `power` is the expected 8.
|
||||
函数 `raiseToPower` 返回基数 (base) 的指数 (exponent) 次幂。 不幸的是，它没有被正确调用 — 修改代码，使`power`的值为 8。
|
||||
|
||||
# --hints--
|
||||
|
||||
Your code should fix the variable `power` so it equals 2 raised to the 3rd power, not 3 raised to the 2nd power.
|
||||
你应修复变量 `power`，使其等于 2 的 3 次方，而不是 3 的 2 次方。
|
||||
|
||||
```js
|
||||
assert(power == 8);
|
||||
```
|
||||
|
||||
Your code should use the correct order of the arguments for the `raiseToPower` function call.
|
||||
你调用 `raiseToPower` 函数时，传递参数的顺序应正确。
|
||||
|
||||
```js
|
||||
assert(code.match(/raiseToPower\(\s*?base\s*?,\s*?exp\s*?\);/g));
|
||||
|
||||
@ -1,6 +1,6 @@
|
||||
---
|
||||
id: 587d7b84367417b2b2512b35
|
||||
title: Catch Misspelled Variable and Function Names
|
||||
title: 捕获拼错的变量名和函数名
|
||||
challengeType: 1
|
||||
forumTopicId: 301186
|
||||
dashedName: catch-misspelled-variable-and-function-names
|
||||
@ -8,41 +8,41 @@ dashedName: catch-misspelled-variable-and-function-names
|
||||
|
||||
# --description--
|
||||
|
||||
The `console.log()` and `typeof` methods are the two primary ways to check intermediate values and types of program output. Now it's time to get into the common forms that bugs take. One syntax-level issue that fast typers can commiserate with is the humble spelling error.
|
||||
`console.log()` 和 `typeof` 方法是检查中间值和程序输出类型的两种主要方法。 现在是时候了解一下 bug 出现的常见的情形。 一个语法级别的问题是打字太快带来的低级拼写错误。
|
||||
|
||||
Transposed, missing, or mis-capitalized characters in a variable or function name will have the browser looking for an object that doesn't exist - and complain in the form of a reference error. JavaScript variable and function names are case-sensitive.
|
||||
变量或函数名的错写、漏写或大小写弄混都会让浏览器尝试查找并不存在的东西，并报出“引用错误”。 JavaScript 变量和函数名称区分大小写。
|
||||
|
||||
# --instructions--
|
||||
|
||||
Fix the two spelling errors in the code so the `netWorkingCapital` calculation works.
|
||||
修复代码中的两个拼写错误，以便 `netWorkingCapital` 计算有效。
|
||||
|
||||
# --hints--
|
||||
|
||||
Check the spelling of the two variables used in the netWorkingCapital calculation, the console output should show that "Net working capital is: 2".
|
||||
检查计算 netWorkingCapital 值时使用的两个变量的拼写是否正确，控制台应该输出 "Net working capital is: 2"。
|
||||
|
||||
```js
|
||||
assert(netWorkingCapital === 2);
|
||||
```
|
||||
|
||||
There should be no instances of mis-spelled variables in the code.
|
||||
代码中不应存在拼写错误的变量。
|
||||
|
||||
```js
|
||||
assert(!code.match(/recievables/g));
|
||||
```
|
||||
|
||||
The `receivables` variable should be declared and used properly in the code.
|
||||
应在代码中声明并正确使用 `receivables` 变量。
|
||||
|
||||
```js
|
||||
assert(code.match(/receivables/g).length == 2);
|
||||
```
|
||||
|
||||
There should be no instances of mis-spelled variables in the code.
|
||||
代码中不应存在拼写错误的变量。
|
||||
|
||||
```js
|
||||
assert(!code.match(/payable;/g));
|
||||
```
|
||||
|
||||
The `payables` variable should be declared and used properly in the code.
|
||||
应在代码中声明并正确使用 `payables` 变量。
|
||||
|
||||
```js
|
||||
assert(code.match(/payables/g).length == 2);
|
||||
|
||||
Reference in New Issue
Block a user