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lodash remove duplicated

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sabareesh
2017-12-14 16:55:06 +05:30
parent e5949c90a5 10ae7ad867
commit c36a0cb565
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130
README.md
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@ -21,7 +21,6 @@
* [Check for palindrome](#check-for-palindrome)
* [Chunk array](#chunk-array)
* [Compact](#compact)
* [Concat](#concat)
* [Count occurrences of a value in array](#count-occurrences-of-a-value-in-array)
* [Current URL](#current-url)
* [Curry](#curry)
@ -39,6 +38,7 @@
* [Get native type of value](#get-native-type-of-value)
* [Get scroll position](#get-scroll-position)
* [Greatest common divisor (GCD)](#greatest-common-divisor-gcd)
* [Group by](#group-by)
* [Hamming distance](#hamming-distance)
* [Head of list](#head-of-list)
* [Initial of list](#initial-of-list)
@ -57,23 +57,31 @@
* [Promisify](#promisify)
* [Random integer in range](#random-integer-in-range)
* [Random number in range](#random-number-in-range)
<<<<<<< HEAD
* [Randomize order of array](#randomize-order-of-array)
* [Redirect to url](#redirect-to-url)
* [Remove](#remove)
=======
* [Redirect to URL](#redirect-to-url)
>>>>>>> 10ae7ad867aaa94d27da81180760d6a0fa84a3a8
* [Reverse a string](#reverse-a-string)
* [RGB to hexadecimal](#rgb-to-hexadecimal)
* [Run promises in series](#run-promises-in-series)
* [Scroll to top](#scroll-to-top)
* [Shuffle array values](#shuffle-array-values)
* [Shuffle array](#shuffle-array)
* [Similarity between arrays](#similarity-between-arrays)
* [Sleep](#sleep)
* [Sort characters in string (alphabetical)](#sort-characters-in-string-alphabetical)
* [Standard deviation](#standard-deviation)
* [Sum of array of numbers](#sum-of-array-of-numbers)
* [Swap values of two variables](#swap-values-of-two-variables)
* [Tail of list](#tail-of-list)
* [Take](#take)
* [Truncate a string](#truncate-a-string)
* [Unique values of array](#unique-values-of-array)
* [URL parameters](#url-parameters)
* [UUID generator](#uuid-generator)
* [Validate email](#validate-email)
* [Validate number](#validate-number)
* [Value or default](#value-or-default)
@ -93,7 +101,7 @@ const anagrams = str => {
// anagrams('abc') -> ['abc','acb','bac','bca','cab','cba']
```
### Array difference (complement)
### Array difference
Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values not contained in `b`.
@ -102,7 +110,7 @@ const difference = (a, b) => { const s = new Set(b); return a.filter(x => !s.has
// difference([1,2,3], [1,2]) -> [3]
```
### Array intersection (Common values between two arrays)
### Array intersection
Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values contained in `b`.
@ -189,13 +197,13 @@ const palindrome = str => {
### Chunk array
Use `Array.apply()` to create a new array, that fits the number of chunks that will be produced.
Use `Array.map()` to map each element of the new array to a chunk the length of `size`.
Use `Array.from()` to create a new array, that fits the number of chunks that will be produced.
Use `Array.slice()` to map each element of the new array to a chunk the length of `size`.
If the original array can't be split evenly, the final chunk will contain the remaining elements.
```js
const chunk = (arr, size) =>
Array.apply(null, {length: Math.ceil(arr.length / size)}).map((v, i) => arr.slice(i * size, i * size + size));
Array.from({length: Math.ceil(arr.length / size)}, (v, i) => arr.slice(i * size, i * size + size));
// chunk([1,2,3,4,5], 2) -> [[1,2],[3,4],5]
```
@ -208,15 +216,6 @@ const compact = (arr) => arr.filter(v => v);
// compact([0, 1, false, 2, '', 3, 'a', 'e'*23, NaN, 's', 34]) -> [ 1, 2, 3, 'a', 's', 34 ]
```
### Concat
Creates a new array concatenating array with any additional arrays and/or values `args` using `Array.concat()`.
```js
const ArrayConcat = (arr, ...args) => arr.concat(...args);
// ArrayConcat([1], [1, 2, 3, [4]]) -> [1, 2, 3, [4]]
```
### Count occurrences of a value in array
Use `Array.reduce()` to increment a counter each time you encounter the specific value inside the array.
@ -393,6 +392,21 @@ const gcd = (x, y) => !y ? x : gcd(y, x % y);
// gcd (8, 36) -> 4
```
### Group by
Use `Array.map()` to map the values of an array to a function or property name.
Use `Array.reduce()` to create an object, where the keys are produced from the mapped results.
```js
const groupBy = (arr, func) =>
(typeof func === 'function' ? arr.map(func) : arr.map(val => val[func]))
.reduce((acc, val, i) => {
acc[val] = acc[val] === undefined ? [arr[i]] : acc[val].concat(arr[i]); return acc;
}, {});
// groupBy([6.1, 4.2, 6.3], Math.floor) -> {4: [4.2], 6: [6.1, 6.3]}
// groupBy(['one', 'two', 'three'], 'length') -> {3: ['one', 'two'], 5: ['three']}
```
### Hamming distance
Use XOR operator (`^`) to find the bit difference between the two numbers, convert to binary string using `toString(2)`.
@ -406,7 +420,7 @@ const hammingDistance = (num1, num2) =>
### Head of list
Return `arr[0]`.
Use `arr[0]` to return the first element of the passed array.
```js
const head = arr => arr[0];
@ -415,7 +429,7 @@ const head = arr => arr[0];
### Initial of list
Return `arr.slice(0,-1)`.
Use `arr.slice(0,-1)`to return all but the last element of the array.
```js
const initial = arr => arr.slice(0, -1);
@ -445,7 +459,7 @@ const initializeArray = (n, value = 0) => Array(n).fill(value);
### Last of list
Return `arr.slice(-1)[0]`.
Use `arr.slice(-1)[0]` to get the last element of the given array.
```js
const last = arr => arr.slice(-1)[0];
@ -591,15 +605,6 @@ const randomInRange = (min, max) => Math.random() * (max - min) + min;
// randomInRange(2,10) -> 6.0211363285087005
```
### Randomize order of array
Use `Array.sort()` to reorder elements, utilizing `Math.random()` to randomize the sorting.
```js
const randomizeOrder = arr => arr.sort((a, b) => Math.random() >= 0.5 ? -1 : 1);
// randomizeOrder([1,2,3]) -> [1,3,2]
```
### Redirect to URL
Use `window.location.href` or `window.location.replace()` to redirect to `url`.
@ -669,17 +674,13 @@ const scrollToTop = _ => {
// scrollToTop()
```
### Shuffle array values
### Shuffle array
Create an array of random values by using `Array.map()` and `Math.random()`.
Use `Array.sort()` to sort the elements of the original array based on the random values.
Use `Array.sort()` to reorder elements, using `Math.random()` in the comparator.
```js
const shuffle = arr => {
let r = arr.map(Math.random);
return arr.sort((a, b) => r[a] - r[b]);
};
// shuffle([1,2,3]) -> [2, 1, 3]
const shuffle = arr => arr.sort(() => Math.random() - 0.5);
// shuffle([1,2,3]) -> [2,3,1]
```
### Similarity between arrays
@ -691,6 +692,21 @@ const similarity = (arr, values) => arr.filter(v => values.includes(v));
// similarity([1,2,3], [1,2,4]) -> [1,2]
```
### Sleep
Delay executing part of an `async` function, by putting it to sleep, returning a `Promise`.
```js
const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));
/*
async function sleepyWork() {
console.log('I\'m going to sleep for 1 second.');
await sleep(1000);
console.log('I woke up after 1 second.');
}
*/
```
### Sort characters in string (alphabetical)
Split the string using `split('')`, `Array.sort()` utilizing `localeCompare()`, recombine using `join('')`.
@ -701,6 +717,24 @@ const sortCharactersInString = str =>
// sortCharactersInString('cabbage') -> 'aabbceg'
```
### Standard deviation
Use `Array.reduce()` to calculate the mean, variance and the sum of the variance of the values, the variance of the values, then
determine the standard deviation.
You can omit the second argument to get the sample standard deviation or set it to `true` to get the population standard deviation.
```js
const standardDeviation = (arr, usePopulation = false) => {
const mean = arr.reduce((acc, val) => acc + val, 0) / arr.length;
return Math.sqrt(
arr.reduce((acc, val) => acc.concat(Math.pow(val - mean, 2)), [])
.reduce((acc, val) => acc + val, 0) / (arr.length - (usePopulation ? 0 : 1))
);
}
// standardDeviation([10,2,38,23,38,23,21]) -> 13.284434142114991 (sample)
// standardDeviation([10,2,38,23,38,23,21], true) -> 12.29899614287479 (population)
```
### Sum of array of numbers
Use `Array.reduce()` to add each value to an accumulator, initialized with a value of `0`.
@ -729,6 +763,17 @@ const tail = arr => arr.length > 1 ? arr.slice(1) : arr;
// tail([1]) -> [1]
```
### Take
Use `Array.slice()` to create a slice of the array with `n` elements taken from the beginning.
```js
const take = (arr, n = 1) => arr.slice(0, n);
// take([1, 2, 3], 5) -> [1, 2, 3]
// take([1, 2, 3], 0) -> []
```
### Truncate a String
Determine if the string's `length` is greater than `num`.
@ -756,7 +801,7 @@ Pass `location.search` as the argument to apply to the current `url`.
```js
const getUrlParameters = url =>
url.match(/([^?=&]+)(=([^&]*))?/g).reduce(
url.match(/([^?=&]+)(=([^&]*))/g).reduce(
(a, v) => (a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1), a), {}
);
// getUrlParameters('http://url.com/page?name=Adam&surname=Smith') -> {name: 'Adam', surname: 'Smith'}
@ -774,6 +819,17 @@ const uuid = _ =>
// uuid() -> '7982fcfe-5721-4632-bede-6000885be57d'
```
### Validate email
Use a regular experssion to check if the email is valid.
Returns `true` if email is valid, `false` if not.
```js
const validateEmail = str =>
/^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/.test(str);
// validateEmail(mymail@gmail.com) -> true
```
### Validate number
Use `!isNaN` in combination with `parseFloat()` to check if the argument is a number.

2
snippets/URL-parameters.md
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@ -5,7 +5,7 @@ Pass `location.search` as the argument to apply to the current `url`.
```js
const getUrlParameters = url =>
url.match(/([^?=&]+)(=([^&]*))?/g).reduce(
url.match(/([^?=&]+)(=([^&]*))/g).reduce(
(a, v) => (a[v.slice(0, v.indexOf('='))] = v.slice(v.indexOf('=') + 1), a), {}
);
// getUrlParameters('http://url.com/page?name=Adam&surname=Smith') -> {name: 'Adam', surname: 'Smith'}

8
snippets/array-concatenation.md Normal file
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@ -0,0 +1,8 @@
### Array concatenation
Use `Array.concat()` to concatenate and array with any additional arrays and/or values, specified in `args`.
```js
const ArrayConcat = (arr, ...args) => arr.concat(...args);
// ArrayConcat([1], [1, 2, 3, [4]]) -> [1, 2, 3, [4]]
```

2
snippets/array-difference.md
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@ -1,4 +1,4 @@
### Array difference (complement)
### Array difference
Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values not contained in `b`.

2
snippets/array-intersection.md
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@ -1,4 +1,4 @@
### Array intersection (Common values between two arrays)
### Array intersection
Create a `Set` from `b`, then use `Array.filter()` on `a` to only keep values contained in `b`.

6
snippets/chunk-array.md
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@ -1,11 +1,11 @@
### Chunk array
Use `Array.apply()` to create a new array, that fits the number of chunks that will be produced.
Use `Array.map()` to map each element of the new array to a chunk the length of `size`.
Use `Array.from()` to create a new array, that fits the number of chunks that will be produced.
Use `Array.slice()` to map each element of the new array to a chunk the length of `size`.
If the original array can't be split evenly, the final chunk will contain the remaining elements.
```js
const chunk = (arr, size) =>
Array.apply(null, {length: Math.ceil(arr.length / size)}).map((v, i) => arr.slice(i * size, i * size + size));
Array.from({length: Math.ceil(arr.length / size)}, (v, i) => arr.slice(i * size, i * size + size));
// chunk([1,2,3,4,5], 2) -> [[1,2],[3,4],5]
```

8
snippets/concat.md
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@ -1,8 +0,0 @@
### Concat
Creates a new array concatenating array with any additional arrays and/or values `args` using `Array.concat()`.
```js
const ArrayConcat = (arr, ...args) => arr.concat(...args);
// ArrayConcat([1], [1, 2, 3, [4]]) -> [1, 2, 3, [4]]
```

14
snippets/group-by.md Normal file
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@ -0,0 +1,14 @@
### Group by
Use `Array.map()` to map the values of an array to a function or property name.
Use `Array.reduce()` to create an object, where the keys are produced from the mapped results.
```js
const groupBy = (arr, func) =>
(typeof func === 'function' ? arr.map(func) : arr.map(val => val[func]))
.reduce((acc, val, i) => {
acc[val] = acc[val] === undefined ? [arr[i]] : acc[val].concat(arr[i]); return acc;
}, {});
// groupBy([6.1, 4.2, 6.3], Math.floor) -> {4: [4.2], 6: [6.1, 6.3]}
// groupBy(['one', 'two', 'three'], 'length') -> {3: ['one', 'two'], 5: ['three']}
```

2
snippets/head-of-list.md
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@ -1,6 +1,6 @@
### Head of list
Return `arr[0]`.
Use `arr[0]` to return the first element of the passed array.
```js
const head = arr => arr[0];

2
snippets/initial-of-list.md
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@ -1,6 +1,6 @@
### Initial of list
Return `arr.slice(0,-1)`.
Use `arr.slice(0,-1)`to return all but the last element of the array.
```js
const initial = arr => arr.slice(0, -1);

2
snippets/last-of-list.md
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@ -1,6 +1,6 @@
### Last of list
Return `arr.slice(-1)[0]`.
Use `arr.slice(-1)[0]` to get the last element of the given array.
```js
const last = arr => arr.slice(-1)[0];

8
snippets/randomize-order-of-array.md
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@ -1,8 +0,0 @@
### Randomize order of array
Use `Array.sort()` to reorder elements, utilizing `Math.random()` to randomize the sorting.
```js
const randomizeOrder = arr => arr.sort((a, b) => Math.random() >= 0.5 ? -1 : 1);
// randomizeOrder([1,2,3]) -> [1,3,2]
```

12
snippets/shuffle-array-values.md
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@ -1,12 +0,0 @@
### Shuffle array values
Create an array of random values by using `Array.map()` and `Math.random()`.
Use `Array.sort()` to sort the elements of the original array based on the random values.
```js
const shuffle = arr => {
let r = arr.map(Math.random);
return arr.sort((a, b) => r[a] - r[b]);
};
// shuffle([1,2,3]) -> [2, 1, 3]
```

8
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@ -0,0 +1,8 @@
### Shuffle array
Use `Array.sort()` to reorder elements, using `Math.random()` in the comparator.
```js
const shuffle = arr => arr.sort(() => Math.random() - 0.5);
// shuffle([1,2,3]) -> [2,3,1]
```

14
snippets/sleep.md Normal file
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@ -0,0 +1,14 @@
### Sleep
Delay executing part of an `async` function, by putting it to sleep, returning a `Promise`.
```js
const sleep = ms => new Promise(resolve => setTimeout(resolve, ms));
/*
async function sleepyWork() {
console.log('I\'m going to sleep for 1 second.');
await sleep(1000);
console.log('I woke up after 1 second.');
}
*/
```

17
snippets/standard-deviation.md Normal file
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@ -0,0 +1,17 @@
### Standard deviation
Use `Array.reduce()` to calculate the mean, variance and the sum of the variance of the values, the variance of the values, then
determine the standard deviation.
You can omit the second argument to get the sample standard deviation or set it to `true` to get the population standard deviation.
```js
const standardDeviation = (arr, usePopulation = false) => {
const mean = arr.reduce((acc, val) => acc + val, 0) / arr.length;
return Math.sqrt(
arr.reduce((acc, val) => acc.concat(Math.pow(val - mean, 2)), [])
.reduce((acc, val) => acc + val, 0) / (arr.length - (usePopulation ? 0 : 1))
);
}
// standardDeviation([10,2,38,23,38,23,21]) -> 13.284434142114991 (sample)
// standardDeviation([10,2,38,23,38,23,21], true) -> 12.29899614287479 (population)
```

10
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@ -0,0 +1,10 @@
### Take
Use `Array.slice()` to create a slice of the array with `n` elements taken from the beginning.
```js
const take = (arr, n = 1) => arr.slice(0, n);
// take([1, 2, 3], 5) -> [1, 2, 3]
// take([1, 2, 3], 0) -> []
```

10
snippets/validate-email.md Normal file
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@ -0,0 +1,10 @@
### Validate email
Use a regular experssion to check if the email is valid.
Returns `true` if email is valid, `false` if not.
```js
const validateEmail = str =>
/^(([^<>()\[\]\\.,;:\s@"]+(\.[^<>()\[\]\\.,;:\s@"]+)*)|(".+"))@((\[[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\])|(([a-zA-Z\-0-9]+\.)+[a-zA-Z]{2,}))$/.test(str);
// validateEmail(mymail@gmail.com) -> true
```