ee1e8abd87
* feat(tools): add seed/solution restore script * chore(curriculum): remove empty sections' markers * chore(curriculum): add seed + solution to Chinese * chore: remove old formatter * fix: update getChallenges parse translated challenges separately, without reference to the source * chore(curriculum): add dashedName to English * chore(curriculum): add dashedName to Chinese * refactor: remove unused challenge property 'name' * fix: relax dashedName requirement * fix: stray tag Remove stray `pre` tag from challenge file. Signed-off-by: nhcarrigan <nhcarrigan@gmail.com> Co-authored-by: nhcarrigan <nhcarrigan@gmail.com>
69 lines
1.3 KiB
Markdown
69 lines
1.3 KiB
Markdown
---
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id: 56bbb991ad1ed5201cd392ce
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title: 使用 unshift() 操作数组
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/ckNDESv'
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forumTopicId: 18239
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dashedName: manipulate-arrays-with-unshift
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---
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# --description--
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你不仅可以`shift`（移出）数组中的第一个元素，你也可以`unshift`（移入）一个元素到数组的头部。
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`.unshift()`函数用起来就像`.push()`函数一样, 但不是在数组的末尾添加元素，而是在数组的头部添加元素。
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# --instructions--
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使用`unshift()`函数把`["Paul",35]`加入到`myArray`的头部。
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# --hints--
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`myArray`应该包含\[["Paul", 35], ["dog", 3]]。
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```js
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assert(
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(function (d) {
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if (
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typeof d[0] === 'object' &&
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d[0][0] == 'Paul' &&
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d[0][1] === 35 &&
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d[1][0] != undefined &&
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d[1][0] == 'dog' &&
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d[1][1] != undefined &&
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d[1][1] == 3
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) {
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return true;
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} else {
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return false;
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}
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})(myArray)
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);
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```
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# --seed--
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## --after-user-code--
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```js
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(function(y, z){return 'myArray = ' + JSON.stringify(y);})(myArray);
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```
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## --seed-contents--
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```js
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// Setup
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var myArray = [["John", 23], ["dog", 3]];
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myArray.shift();
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// Only change code below this line
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```
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# --solutions--
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```js
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var myArray = [["John", 23], ["dog", 3]];
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myArray.shift();
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myArray.unshift(["Paul", 35]);
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```
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