Various methods of sorting arrays in php_PHP tutorial

When we learn programming, we know that sorting methods include bubble sorting, quick sorting, selection sorting, etc., and the simultaneous sorting method Divided into two categories internal and external.

Sort method of array
Divided into two categories:
1. Internal (memory) sorting
2. External sorting (the amount of data is too large to be stored in the memory, so external sorting is required
Storage)

----------------
Sorting is a basic skill for a programmer
1: Internal sorting
(1) Commutative sorting
1. Bubble method

The default transfer of arrays is value transfer, not address transfer
We will talk about object types later. The default transfer of objects is address transfer

//Optimize, encapsulate the bubble sorting method into a function to facilitate future use

$myarr[$j]= $myarr[$j+1];

The code is as follows

代码如下	复制代码
function bubbleSort(&$myarr){ $temp=0;//定义一个中间变量 //外层循环 for($i=0;$i<count($myarr)-1;$i++){ for($j=0;$j<count($myarr)-1-$i; $j++){ if($myarr[$j]>$myarr[$j +1]){ $temp=$myarr[$j]; $myarr[$j]= $myarr[$j+1]; $myarr[$j+1]= $temp; } } } } $arry=array(2,6,-4,7,9,0); bubbleSort($arry); print_r($arry);

Copy code

function bubbleSort(&$myarr){

$temp=0;//Define an intermediate variable

代码如下	复制代码
function selectSort(&$myarr){ $temp=0; for($i=0;$i<count($myarr)-1;$i++){ //假设$i就是最小的数 $minval=$myarr[$i]; //记录我认为的最小数的下标 $minIndex=$i; for($j=$i+1;$j<count($myarr);$j+ +){ //说明我们认为的最小值，不是最小 if($minval>$myarr[$j]){ $minval=$myarr[$j]; $minIndex=$j; } } //最后交换 $temp=$myarr[$i]; $myarr[$i]=$myarr[$minIndex]; $myarr[$minIndex]=$temp; } }

//Outer loop

for($i=0;$i<count($myarr)-1;$i++){

for($j=0;$j<count($myarr)-1-$i;

$j++){

if($myarr[$j]>$myarr[$j

+1]){

$temp=$myarr[$j];

$myarr[$j+1]= $temp;

}

} } } $arry=array(2,6,-4,7,9,0); bubbleSort($arry); print_r($arry); 2. Quick sorting method (magically fast, involving recursion)

3. Selection sorting method

The code is as follows

Copy code

function selectSort(&$myarr){ $temp=0; for($i=0;$i<count($myarr)-1;$i++){<🎜> //Assume $i is the smallest number<🎜> $minval=$myarr[$i];<🎜> //Record the subscript of the smallest number I think <🎜> $minIndex=$i;<🎜> <🎜>for($j=$i+1;$j<count($myarr);$j+ <🎜> +){<🎜> //Explain that the minimum value we think is not the minimum<🎜> if($minval>$myarr[$j]){ $minval=$myarr[$j]; $minIndex=$j; } } //Final exchange $temp=$myarr[$i]; $myarr[$i]=$myarr[$minIndex]; $myarr[$minIndex]=$temp; } } 4. Insertion sort method Query speed: bubble sorting method<selection sorting method<insertion sorting method My personal favorite is exchange sorting, which is what everyone calls the bubble sorting method. This method is easier to use, but it is not suitable for sorting large amounts of data. http://www.bkjia.com/PHPjc/631630.htmlwww.bkjia.comtruehttp: //www.bkjia.com/PHPjc/631630.htmlTechArticleWhen we learn programming, we know that sorting methods include bubble sorting, quick sorting, selection sorting, etc. At the same time Sorting methods are divided into two categories: internal and external. The sorting method of the array is divided into two...