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>
88 lines
1.7 KiB
Markdown
88 lines
1.7 KiB
Markdown
---
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id: 56bbb991ad1ed5201cd392cd
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title: Manipulate Arrays With shift()
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/cRbVETW'
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forumTopicId: 18238
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dashedName: manipulate-arrays-with-shift
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---
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# --description--
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`pop()` always removes the last element of an array. What if you want to remove the first?
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That's where `.shift()` comes in. It works just like `.pop()`, except it removes the first element instead of the last.
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Example:
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```js
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var ourArray = ["Stimpson", "J", ["cat"]];
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var removedFromOurArray = ourArray.shift();
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// removedFromOurArray now equals "Stimpson" and ourArray now equals ["J", ["cat"]].
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```
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# --instructions--
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Use the `.shift()` function to remove the first item from `myArray`, assigning the "shifted off" value to `removedFromMyArray`.
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# --hints--
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`myArray` should now equal `[["dog", 3]]`.
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```js
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assert(
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(function (d) {
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if (d[0][0] == 'dog' && d[0][1] === 3 && d[1] == undefined) {
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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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`removedFromMyArray` should contain `["John", 23]`.
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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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d[0] == 'John' &&
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d[1] === 23 &&
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typeof removedFromMyArray === 'object'
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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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})(removedFromMyArray)
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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) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);
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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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// Only change code below this line
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var removedFromMyArray;
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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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// Only change code below this line
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var removedFromMyArray = myArray.shift();
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```
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