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Add weightedSample snippet

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This commit is contained in:
Angelos Chalaris
2019-12-31 11:34:26 +02:00
parent 6ea98b02ad
commit 21b0ab5c65
10 changed files with 164 additions and 95 deletions
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16
snippet_data/snippetList.json
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}
},
{
"id": "weightedSample",
"type": "snippetListing",
"title": "weightedSample",
"attributes": {
"text": "Returns a random element from an array, using the provided `weights` as the probabilities for each element.\n\nUse `Array.prototype.reduce()` to create an array of partial sums for each value in `weights`.\nUse `Math.random()` to generate a random number and `Array.prototype.findIndex()` to find the correct index based on the array previously produced.\nFinally, return the element of `arr` with the produced index.\n\n\n",
"tags": [
"array",
"random",
"advanced"
]
},
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66
snippet_data/snippets.json
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{
"id": "weightedSample",
"title": "weightedSample",
"type": "snippet",
"attributes": {
"fileName": "weightedSample.md",
"text": "Returns a random element from an array, using the provided `weights` as the probabilities for each element.\n\nUse `Array.prototype.reduce()` to create an array of partial sums for each value in `weights`.\nUse `Math.random()` to generate a random number and `Array.prototype.findIndex()` to find the correct index based on the array previously produced.\nFinally, return the element of `arr` with the produced index.\n\n\n",
"codeBlocks": {
"es6": "const weightedSample = (arr, weights) => {\n let roll = Math.random();\n return arr[\n weights\n .reduce((acc, w, i) =>\n i === 0 ? [w] : [...acc, acc[acc.length - 1] + w],\n []\n )\n .findIndex((v, i, s) =>\n roll >= (i === 0 ? 0 : s[i - 1]) && roll < v\n )\n ];\n}",
"es5": "function _toConsumableArray(arr) { return _arrayWithoutHoles(arr) || _iterableToArray(arr) || _nonIterableSpread(); }\n\nfunction _nonIterableSpread() { throw new TypeError(\"Invalid attempt to spread non-iterable instance\"); }\n\nfunction _iterableToArray(iter) { if (Symbol.iterator in Object(iter) || Object.prototype.toString.call(iter) === \"[object Arguments]\") return Array.from(iter); }\n\nfunction _arrayWithoutHoles(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = new Array(arr.length); i < arr.length; i++) { arr2[i] = arr[i]; } return arr2; } }\n\nvar weightedSample = function weightedSample(arr, weights) {\n var roll = Math.random();\n return arr[weights.reduce(function (acc, w, i) {\n return i === 0 ? [w] : [].concat(_toConsumableArray(acc), [acc[acc.length - 1] + w]);\n }, []).findIndex(function (v, i, s) {\n return roll >= (i === 0 ? 0 : s[i - 1]) && roll < v;\n })];\n};",
"example": "weightedSample([3, 7, 9, 11], [0.1, 0.2, 0.6, 0.1]); // 9"
},
"tags": [
"array",
"random",
"advanced"
]
},
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