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Angelos Chalaris
2017-12-12 12:12:44 +02:00
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README.md
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@ -83,10 +83,10 @@ var capitalize = str => str.slice(0, 1).toUpperCase() + str.slice(1);
### Count occurrences of a value in array ### Count occurrences of a value in array
Use `filter()` to create an array containing only the items with the specified value, count them using `length`. Use `reduce()` to increment a counter each time you encounter the specific value inside the array.
```js ```js
var countOccurrences = (arr, value) => arr.filter(v => v === value).length; var countOccurrences = (arr, value) => arr.reduce((a, v) => v===value ? a + 1 : a + 0, 0);
``` ```
### Current URL ### Current URL

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snippets/count-occurrences-of-a-value-in-array.md
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### Count occurrences of a value in array ### Count occurrences of a value in array
Use `filter()` to create an array containing only the items with the specified value, count them using `length`. Use `reduce()` to increment a counter each time you encounter the specific value inside the array.
```js
var countOccurrences = (arr, value) => arr.filter(v => v === value).length;
```
Use reduce() to increment a counter each time you encounter the specific value; does not create new array like filter().
```js ```js
var countOccurrences = (arr, value) => arr.reduce((a, v) => v===value ? a + 1 : a + 0, 0); var countOccurrences = (arr, value) => arr.reduce((a, v) => v===value ? a + 1 : a + 0, 0);