mirror of https://github.com/jkjoy/sunpeiwen.git
50 lines
1020 B
JavaScript
50 lines
1020 B
JavaScript
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'use strict';
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/**
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* Array random slice with items count.
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* @param {Array} arr
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* @param {Number} num, number of sub items.
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* @return {Array}
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*/
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exports.randomSlice = function randomSlice(arr, num) {
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if (!num || num >= arr.length) {
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return arr.slice();
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}
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var index = Math.floor(Math.random() * arr.length);
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var a = [];
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for (var i = 0, j = index; i < num; i++) {
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a.push(arr[j++]);
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if (j === arr.length) {
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j = 0;
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}
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}
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return a;
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};
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/**
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* Remove one exists element from an array
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* @param {Array} arr
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* @param {Number} index - remove element index
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* @return {Array} the array instance
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*/
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exports.spliceOne = function spliceOne(arr, index) {
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if (index < 0) {
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index = arr.length + index;
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// still negative, not found element
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if (index < 0) {
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return arr;
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}
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}
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// don't touch
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if (index >= arr.length) {
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return arr;
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}
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for (var i = index, k = i + 1, n = arr.length; k < n; i += 1, k += 1) {
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arr[i] = arr[k];
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}
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arr.pop();
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return arr;
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};
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