php数组之数组的元素值进行降序排序rsort()函数

<?php
$my_array = array("a" => "Dog", "b" => "Cat", "c" => "Horse");
rsort($my_array);
print_r($my_array);
?>

输出：

Array
(
[0] => Horse
[1] => Dog
[2] => Cat
)

$data[] = array('volume' => 67, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 1);
$data[] = array('volume' => 85, 'edition' => 6);
$data[] = array('volume' => 98, 'edition' => 2);
$data[] = array('volume' => 86, 'edition' => 6);
$data[] = array('volume' => 67, 'edition' => 7);

volume | edition
-------+--------
98 |       2
86 |       1
86 |       6
85 |       6
67 |       2
67 |       7

<?php
$a=array("a"=>"Horse","b"=>"Cat","c"=>"Dog");
print_r(array_keys($a));
?>

输出：

Array ( [0] => a [1] => b [2] => c )

<?php
$a=array("a"=>"Horse","b"=>"Cat","c"=>"Dog");
print_r(array_keys($a,"Dog"));
?>

输出：

Array ( [0] => c)

<?php
$a=array(10,20,30,"10");
print_r(array_keys($a,"10",false));
?>

输出：

Array ( [0] => 0 [1] => 3 )

<?php
$a=array(10,20,30,"10");
print_r(array_keys($a,"10",true));
?>

输出：

Array ( [0] => 3)

<?php
$stack = array("orange", "banana", "apple", "raspberry");
$fruit = array_pop($stack);
print_r($stack);
?>
经过此操作后，$stack 将只有 3 个单元：

Array
(
    [0] => orange
    [1] => banana
    [2] => apple
)

<?
$array = array('ccc','www.111cn.net','abc','111cn.net');
$arrtmp = array();
for( $i=0;$i<count($array)-1;$i++ )
{
 $arrtmp[] = $array[$i];
}
print_r($arrtmp);

Array
(
    [0] => ccc
    [1] => www.111cn.net
    [2] => abc
)

?>

<?php
function array_pshift(&$array) {
    $keys = array_keys($array);
    $key = array_shift($keys);
    $element = $array[$key];
    unset($array[$key]);
    return $element;
}
?>

<?php
header('Content-Type: text/html; charset=utf-8');
//   简单冒泡算法      0 1 2 3 4
$a = array(5,4,3,2,1);  //5
echo  "比较54321   <br /><hr />";
function  mp($a){  //传值 要是数组
        //i=1 i<5 i++
        for($i=0;$i<count($a);$i++){ 
                /* j=3 j<i  j-- 
                 * 这里为什么要-2呢
                 * 因为数组是从0开始的 所以要-1
                 * 然后 一会要比较后一位 和倒数第二位  所以 要-2
                 * 当然 -1  也可以 只要把 $a[j+1]改成$a[j]  然后把$a[j] 改成$a[j-1] 即可
                 */
                for ($j=count($a)-2;$j>=$i;$j--){ 
                        //判断数组最大的位数  和第二大的相比
                         if ($a[$j+1]<$a[$j]){   
                                 echo  $a[$j+1],'------小于-----',$a[$j],'----------排列前：',fn($a);
               //如果最大的小于第二大的就换位置
                                 $tmp = $a[$j+1];  
                                   $a[$j+1]=$a[$j];
                                   $a[$j]=$tmp;
                                   echo '------------排列后：',fn($a),'<br><hr>';
                         }
                        
                }
               
               
        }
        return $a;
}

echo  fn(mp($a));

function fn($arr){
        foreach ($arr as $value){
                echo  $value;
        }       
}

   
?>