](https://github.com/Chalarangelo)
](https://github.com/Pl4gue)
](https://github.com/fejes713)
](https://github.com/kingdavidmartins)
](https://github.com/iamsoorena)lcm(12, 7); // 84
lcm([1, 3, 4], 5); // 60
+Returns the n maximum elements from the provided array. If n is greater than or equal to the provided array's length than return the original array(sorted in descending order).
Sort's the array's shallow copy in descending order and returns the first n elements
Skip the second argument to get a single element(in the form of a array)
const maxN = (arr, n = 1) => [...arr].sort((a, b) => b - a).slice(0, n);
+maxN([1, 2, 3]); // [3]
+maxN([1, 2, 3], 2); // [3,2]
+maxN([1, 2, 3], 4); // [3,2,1]
Returns the median of an array of numbers.
Find the middle of the array, use Array.sort() to sort the values. Return the number at the midpoint if length is odd, otherwise the average of the two middle numbers.
const median = arr => {
const mid = Math.floor(arr.length / 2),
nums = [...arr].sort((a, b) => a - b);
@@ -724,6 +728,10 @@ lcm([1, 3, 4], 5); // 60
};
median([5, 6, 50, 1, -5]); // 5
median([0, 10, -2, 7]); // 3.5
+Returns the n minimum elements from the provided array. If n is greater than or equal to the provided array's length than return the original array(sorted in ascending order).
Sort's the array's shallow copy in ascending order and returns the first n elements
Skip the second argument to get a single element(in the form of a array)
const minN = (arr, n = 1) => [...arr].sort((a, b) => a - b).slice(0, n);
+minN([1, 2, 3]); // [1]
+minN([1, 2, 3], 2); // [1,2]
+minN([1, 2, 3], 4); // [1,2,3]
Uses the percentile formula to calculate how many numbers in the given array are less or equal to the given value.
Use Array.reduce() to calculate how many numbers are below the value and how many are the same value and apply the percentile formula.
const percentile = (arr, val) =>
100 * arr.reduce((acc, v) => acc + (v < val ? 1 : 0) + (v === val ? 0.5 : 0), 0) / arr.length;
percentile([1, 2, 3, 4, 5, 6, 7, 8, 9, 10], 6); // 55
diff --git a/snippets/memoize.md b/snippets/memoize.md
index c1b6b1343..856375a69 100644
--- a/snippets/memoize.md
+++ b/snippets/memoize.md
@@ -2,13 +2,20 @@
Returns the memoized (cached) function.
-Use `Object.create(null)` to create an empty object without `Object.prototype` (so that those properties are not resolved if the input value is something like `'hasOwnProperty'`).
-Return a function which takes a single argument to be supplied to the memoized function by first checking if the function's output for that specific input value is already cached, or store and return it if not.
+Create an empty cache by instantiating a new `Map` object.
+Return a function which takes a single argument to be supplied to the memoized function by first checking if the function's output for that specific input value is already cached, or store and return it if not. The `function` keyword must be used in order to allow the memoized function to have its `this` context changed if necessary.
+Allow access to the `cache` by setting it as a property on the returned function.
```js
const memoize = fn => {
- const cache = Object.create(null);
- return value => cache[value] || (cache[value] = fn(value));
+ const cache = new Map();
+ const cached = function(val) {
+ return cache.has(val)
+ ? cache.get(val)
+ : cache.set(val, fn.call(this, val)) && cache.get(val);
+ };
+ cached.cache = cache;
+ return cached;
};
```
@@ -17,4 +24,5 @@ const memoize = fn => {
const anagramsCached = memoize(anagrams);
anagramsCached('javascript'); // takes a long time
anagramsCached('javascript'); // returns virtually instantly since it's now cached
+console.log(anagramsCached.cache); // Map
```