Files
Kristofer Koishigawa bcc9beff1f feat(curriculum): introduce let and const earlier (#43133)
* fix: move "Explore Differences Between..." to basic JS, update seed and tests

* fix: resequence "Declare String Variables"

* fix: move "Declare a Read-Only Variable..." to basic JS, update seed and tests

* fix: revert changes to non-English "Explore Differences Between..." test text

* fix: revert test strings, solutions, and seeds for non-English challenges

* fix: update "Declare String Variables" description

* fix: sync quotation marks in description and seed

* fix: modify note in "Declare a Read-Only..." challenge

* fix: update operator and compound assignment challenges

* fix: update string challenges

* fix: update array and array method challenges

* fix: update function and scope challenges, resequence slightly

* fix: "Word Blanks" solution

* fix: add spacing to seed

* fix: concatenating += challenge spacing

* fix: appending variables to strings spacing

* fix: find the length of a string spacing

* fix: removed instances of removedFromMyArray = 0

* fix: switch challenges

* fix: function argument and param spacing

* fix: update counting cards, object challenges, and record collection

* fix: finish rest of Basic JS section

* fix: introducing else statements solution

* fix: update spacing and wording

* fix: update wording for const challenge

* fix: update functional programming challenges

* fix: intermediate algorithms and cert challenges

* fix: revert some spacing and remove comments for fp challenge solutions

* feat: add notes with links to moved let and const challenges in first two es6 challenges

* fix: update es6 intro text

* Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/concatenating-strings-with-the-plus-equals-operator.md

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

* Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/finding-a-remainder-in-javascript.md

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

* Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/global-scope-and-functions.md

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

* Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/iterate-through-an-array-with-a-for-loop.md

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

* Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/iterate-through-an-array-with-a-for-loop.md

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

* Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/functional-programming/implement-map-on-a-prototype.md

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

* Update curriculum/challenges/english/02-javascript-algorithms-and-data-structures/basic-javascript/declare-a-read-only-variable-with-the-const-keyword.md

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>

* fix: concatenating strings with plus operator seed

* fix: add comments back to Declare a Read-Only Variable... seed

* feat: add es6 to basic javascript redirect tests for let and const challenges

* fix: revert "Concatenating Strings with Plus Operator" seed

* fix: move test file to cypress/integration/learn/redirects, separate redirect tests

Co-authored-by: Shaun Hamilton <shauhami020@gmail.com>
2021-10-25 17:55:58 +01:00

89 lines
1.8 KiB
Markdown

---
id: 56bbb991ad1ed5201cd392cd
title: Manipulate Arrays With shift()
challengeType: 1
videoUrl: 'https://scrimba.com/c/cRbVETW'
forumTopicId: 18238
dashedName: manipulate-arrays-with-shift
---
# --description--
`pop()` always removes the last element of an array. What if you want to remove the first?
That's where `.shift()` comes in. It works just like `.pop()`, except it removes the first element instead of the last.
Example:
```js
const ourArray = ["Stimpson", "J", ["cat"]];
const removedFromOurArray = ourArray.shift();
```
`removedFromOurArray` would have a value of the string `Stimpson`, and `ourArray` would have `["J", ["cat"]]`.
# --instructions--
Use the `.shift()` function to remove the first item from `myArray` and assign the "shifted off" value to a new variable, `removedFromMyArray`.
# --hints--
`myArray` should now equal `[["dog", 3]]`.
```js
assert(
(function (d) {
if (d[0][0] == 'dog' && d[0][1] === 3 && d[1] == undefined) {
return true;
} else {
return false;
}
})(myArray)
);
```
`removedFromMyArray` should contain `["John", 23]`.
```js
assert(
(function (d) {
if (
d[0] == 'John' &&
d[1] === 23 &&
typeof removedFromMyArray === 'object'
) {
return true;
} else {
return false;
}
})(removedFromMyArray)
);
```
# --seed--
## --after-user-code--
```js
if (typeof removedFromMyArray !== 'undefined') (function(y, z){return 'myArray = ' + JSON.stringify(y) + ' & removedFromMyArray = ' + JSON.stringify(z);})(myArray, removedFromMyArray);
```
## --seed-contents--
```js
// Setup
const myArray = [["John", 23], ["dog", 3]];
// Only change code below this line
```
# --solutions--
```js
const myArray = [["John", 23], ["dog", 3]];
// Only change code below this line
const removedFromMyArray = myArray.shift();
```