diff --git a/README.md b/README.md index f185c714d..6659888fa 100644 --- a/README.md +++ b/README.md @@ -64,6 +64,7 @@ * [`quickSort`](#quicksort) * [`remove`](#remove) * [`sample`](#sample) +* [`sampleSize`](#samplesize) * [`shuffle`](#shuffle) * [`similarity`](#similarity) * [`symmetricDifference`](#symmetricdifference) @@ -260,15 +261,6 @@ -### _Uncategorized_ - -
-View contents - -* [`sampleSize`](#samplesize) - -
- --- ## 🔌 Adapter @@ -1199,6 +1191,38 @@ sample([3, 7, 9, 11]); // 9
[⬆ Back to top](#table-of-contents) +### sampleSize + +Gets `n` random elements at unique keys from `array` up to the size of `array`. + +Shuffle the array using the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle). +Use `Array.slice()` to get the first `n` elements. +Omit the second argument, `n` to get only one element at random from the array. + +```js +const sampleSize = ([...arr], n = 1) => { + let m = arr.length; + while (m) { + const i = Math.floor(Math.random() * m--); + [arr[m], arr[i]] = [arr[i], arr[m]]; + } + return arr.slice(0, n); +}; +``` + +
+Examples + +```js +sampleSize([1, 2, 3], 2); // [3,1] +sampleSize([1, 2, 3], 4); // [2,3,1] +``` + +
+ +
[⬆ Back to top](#table-of-contents) + + ### shuffle Randomizes the order of the values of an array, returning a new array. @@ -4370,35 +4394,6 @@ yesNo('Foo', true); // true
[⬆ Back to top](#table-of-contents) ---- - ## _Uncategorized_ - -### sampleSize - -Gets `n` random elements at unique keys from `array` up to the size of `array`. - -Shuffle the array using the [Fisher-Yates algorithm](https://github.com/chalarangelo/30-seconds-of-code#shuffle). -Use `Array.slice()` to get the first `n` elements. -Omit the second argument, `n` to get only one element at random from the array. - -```js -const sampleSize = ([...arr], n = 1) => { - let m = arr.length; - while (m) { - const i = Math.floor(Math.random() * m--); - [arr[m], arr[i]] = [arr[i], arr[m]]; - } - return arr.slice(0, n); -}; -``` - -```js -sampleSize([1, 2, 3], 2); // [3,1] -sampleSize([1, 2, 3], 4); // [2,3,1] -``` - -
[⬆ back to top](#table-of-contents) - ## Collaborators diff --git a/docs/index.html b/docs/index.html index 6a66cb59d..f36e25510 100644 --- a/docs/index.html +++ b/docs/index.html @@ -59,7 +59,7 @@ wrapper.appendChild(box); box.appendChild(el); }); - }

 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.

 

Adapter

call

Given a key and a set of arguments, call them when given a context. Primarily useful in composition.

Use a closure to call a stored key with stored arguments.

const call = (key, ...args) => context => context[key](...args);
+    }
 30 seconds of code Curated collection of useful JavaScript snippets that you can understand in 30 seconds or less.
 
Adapter
call
Given a key and a set of arguments, call them when given a context. Primarily useful in composition.
Use a closure to call a stored key with stored arguments.
const call = (key, ...args) => context => context[key](...args);
 
Promise.resolve([1, 2, 3])
   .then(call('map', x => 2 * x))
   .then(console.log); //[ 2, 4, 6 ]
@@ -236,6 +236,16 @@ quickSort([4, 1, 3, 2], true); // [4,3,2,1]
 
remove([1, 2, 3, 4], n => n % 2 == 0); // [2, 4]
 

sample
Returns a random element from an array.
Use Math.random() to generate a random number, multiply it by length and round it of to the nearest whole number using Math.floor(). This method also works with strings.
const sample = arr => arr[Math.floor(Math.random() * arr.length)];
 
sample([3, 7, 9, 11]); // 9
+

sampleSize
Gets n random elements at unique keys from array up to the size of array.
Shuffle the array using the Fisher-Yates algorithm. Use Array.slice() to get the first n elements. Omit the second argument, n to get only one element at random from the array.
const sampleSize = ([...arr], n = 1) => {
+  let m = arr.length;
+  while (m) {
+    const i = Math.floor(Math.random() * m--);
+    [arr[m], arr[i]] = [arr[i], arr[m]];
+  }
+  return arr.slice(0, n);
+};
+
sampleSize([1, 2, 3], 2); // [3,1]
+sampleSize([1, 2, 3], 4); // [2,3,1]
 

shuffle
Randomizes the order of the values of an array, returning a new array.
Uses the Fisher-Yates algoritm to reorder the elements of the array, based on the Lodash implementation, but as a pure function.
const shuffle = ([...arr]) => {
   let m = arr.length;
   while (m) {
@@ -905,14 +915,4 @@ console.log(sdbm('age')); // 808122783
 yesNo('yes'); // true
 yesNo('No'); // false
 yesNo('Foo', true); // true
-

Uncategorized
sampleSize
Gets n random elements at unique keys from array up to the size of array.
Shuffle the array using the Fisher-Yates algorithm. Use Array.slice() to get the first n elements. Omit the second argument, n to get only one element at random from the array.
const sampleSize = ([...arr], n = 1) => {
-  let m = arr.length;
-  while (m) {
-    const i = Math.floor(Math.random() * m--);
-    [arr[m], arr[i]] = [arr[i], arr[m]];
-  }
-  return arr.slice(0, n);
-};
-
sampleSize([1, 2, 3], 2); // [3,1]
-sampleSize([1, 2, 3], 4); // [2,3,1]
 


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