80 lines
2.1 KiB
Markdown
80 lines
2.1 KiB
Markdown
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---
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id: cf1111c1c11feddfaeb5bdef
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title: Iterate with JavaScript For Loops
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challengeType: 1
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videoUrl: 'https://scrimba.com/c/c9yNVCe'
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forumTopicId: 18219
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dashedName: iterate-with-javascript-for-loops
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---
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# --description--
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You can run the same code multiple times by using a loop.
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The most common type of JavaScript loop is called a `for` loop because it runs for a specific number of times.
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For loops are declared with three optional expressions separated by semicolons:
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`for (a; b; c)`, where `a` is the intialization statement, `b` is the condition statement, and `c` is the final expression.
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The initialization statement is executed one time only before the loop starts. It is typically used to define and setup your loop variable.
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The condition statement is evaluated at the beginning of every loop iteration and will continue as long as it evaluates to `true`. When the condition is `false` at the start of the iteration, the loop will stop executing. This means if the condition starts as false, your loop will never execute.
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The final expression is executed at the end of each loop iteration, prior to the next condition check and is usually used to increment or decrement your loop counter.
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In the following example we initialize with `i = 0` and iterate while our condition `i < 5` is true. We'll increment `i` by `1` in each loop iteration with `i++` as our final expression.
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```js
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var ourArray = [];
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for (var i = 0; i < 5; i++) {
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ourArray.push(i);
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}
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```
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`ourArray` will now have the value `[0,1,2,3,4]`.
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# --instructions--
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Use a `for` loop to push the values 1 through 5 onto `myArray`.
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# --hints--
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You should be using a `for` loop for this.
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```js
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assert(/for\s*\([^)]+?\)/.test(code));
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```
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`myArray` should equal `[1,2,3,4,5]`.
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```js
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assert.deepEqual(myArray, [1, 2, 3, 4, 5]);
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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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if (typeof myArray !== "undefined"){(function(){return 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 = [];
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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 = [];
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for (var i = 1; i < 6; i++) {
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myArray.push(i);
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}
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```
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