JS disrupt the Array (random sorting to generate random numbers that are not repeated)

The method to achieve random sorting of arrays is actually very simple, but Baidu found that there are a large number of such instances, but I strongly recommend these three instances. The random sorting written by a foreign user is not repeated, it's not bad. Let's take a look.

I think it is the most streamlined method that has been written by foreign people on the Internet:

Program code

// Use the Math. random () function to generate 0 ~ The random number between 1 and 0.5 is compared, and-1 or 1 is returned.

The Code is as follows:	Copy code
Function randomsort (a, B ){ Return Math. random ()>. 5? -1: 1; } Var arr = [1, 2, 3, 4, 5]; Var arr2 = arr. sort (randomsort ); Alert (arr2 );

Here we will introduce the sort () function. In JS, an Array object has a built-in function:

Arrayobj. sort ([sortfunction])

This method sorts Array objects appropriately. During execution, no new Array objects are created.

SortFunction is optional.

Is the name of the function used to determine the order of elements. If this parameter is omitted, the elements are listed in ascending order of ASCII characters.
The sortFunction method has two parameters. Represent the two array items for each sort comparison. This parameter is executed every time two array items are compared during sort () sorting, and two compared array items are passed as parameters to this function. When the return value of the function is 1, the order of two array items is exchanged. Otherwise, the order is not exchanged.

Some of my domestic friends wrote

The Code is as follows:

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// Obtain the random number in the array // HF. Math. RandomNumbers is the prefix and can be defined by yourself. It mainly depends on the logic code. HF. Math. RandomNumbers = function (startNum, endNum, count, repeat ){ Var ret = []; If (repeat ){ For (var I = 0; I <count; I ++ ){ Ret [I] = HF. Math. Random (startNum, endNum ); } Return ret; } Var tmp = []; Var I = 0; For (var s = startNum; s <= endNum; s ++ ){ Tmp [I ++] = s; } Var l = tmp. length; For (I = 0; I <count; I ++ ){ Ret [I] = HF. Array. Remove (tmp, HF. Math. Random (0, -- l )); } Return ret; }

Examples of Generating Random Arrays

The Code is as follows:

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// Define an array for storing the random numbers generated Var array = new Array ();   // Generate a random number N times in a loop For (var I = 0; I ++ ){ // Generate only 10 random numbers If (array. length <10 ){ GenerateRandom (10 ); } Else { Break; } }   // Cyclically traverse the random number Array For (var I = 0; I <array. length; I ++ ){ Alert (array [I]); }   // Method for generating random numbers Function generateRandom (count ){ Var rand = parseInt (Math. random () * count ); For (var I = 0; I <array. length; I ++ ){ If (array [I] = rand ){ Return false; } } Array. push (rand ); }