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>
66 lines
1.8 KiB
Markdown
66 lines
1.8 KiB
Markdown
---
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id: 587d7b7a367417b2b2512b12
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title: Copy Array Items Using slice()
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challengeType: 1
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forumTopicId: 301158
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dashedName: copy-array-items-using-slice
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---
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# --description--
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The next method we will cover is `slice()`. Rather than modifying an array, `slice()` copies or *extracts* a given number of elements to a new array, leaving the array it is called upon untouched. `slice()` takes only 2 parameters — the first is the index at which to begin extraction, and the second is the index at which to stop extraction (extraction will occur up to, but not including the element at this index). Consider this:
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```js
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let weatherConditions = ['rain', 'snow', 'sleet', 'hail', 'clear'];
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let todaysWeather = weatherConditions.slice(1, 3);
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// todaysWeather equals ['snow', 'sleet'];
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// weatherConditions still equals ['rain', 'snow', 'sleet', 'hail', 'clear']
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```
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In effect, we have created a new array by extracting elements from an existing array.
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# --instructions--
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We have defined a function, `forecast`, that takes an array as an argument. Modify the function using `slice()` to extract information from the argument array and return a new array that contains the elements `'warm'` and `'sunny'`.
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# --hints--
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`forecast` should return `["warm", "sunny"]`
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```js
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assert.deepEqual(
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forecast(['cold', 'rainy', 'warm', 'sunny', 'cool', 'thunderstorms']),
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['warm', 'sunny']
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);
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```
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The `forecast` function should utilize the `slice()` method
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```js
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assert(/\.slice\(/.test(code));
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```
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# --seed--
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## --seed-contents--
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```js
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function forecast(arr) {
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// Only change code below this line
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return arr;
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}
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// Only change code above this line
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console.log(forecast(['cold', 'rainy', 'warm', 'sunny', 'cool', 'thunderstorms']));
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```
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# --solutions--
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```js
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function forecast(arr) {
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return arr.slice(2,4);
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}
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```
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