PHP常用数组函数

PHP常用的数组函数

一、数组排序函数

1.sort(); 以升序对数组排序。

1 <?php
2 $color=array('green','red','yellow','black','white'); 
3 sort($color); 
4 print_r($color); 
5 ?> 



结果输出：

Array
(
[0] => black
[1] => green
[2] => red
[3] => white
[4] => yellow
)
 
 
备注：按升序对数组进行排序

2.rsort(); 以降序对数组排序

1 <?php
2 $color=array('green','red','yellow','black','white');
3 rsort($color);
4 print_r($color);
5 ?>

结果输出：

Array
(
[0] => yellow
[1] => white
[2] => red
[3] => green
[4] => black
)



备注：按降序对数组进行排序

3.ksort() ；按照键名对关联数组进行升序排序。

1 <?php
2 $arr = ['c'=>'apple','f'=>'tree','a'=>'father','s'=>'teacher','g'=>'student',];
3 ksort($arr); 
4 print_r($arr); 
5 ?>

结果输出：

Array
(
[a] => father
[c] => apple
[f] => tree
[g] => student
[s] => teacher
)
 
备注：按键名升序排序

4.krsort() 函数对关联数组按照键名进行降序排序。

1 <?php
2 $arr = ['c'=>'apple','f'=>'tree','a'=>'father','s'=>'teacher','g'=>'student',];
3 krsort($arr); 
4 print_r($arr); 
5 ?>

结果输出：

Array
(
[s] => teacher
[g] => student
[f] => tree
[c] => apple
[a] => father
)
 
备注：按键名降序排序

5.asort(); 按照键值对关联数组进行升序排序。

1 <?php
2 $arr=['c'=>'apple','f'=>'tree','a'=>'father','s'=>'teacher','g'=>'student',]; 
3 asort($arr); 
4 print_r($arr); 
5 ?> 
结果输出：

Array
(
[c] => apple
[a] => father
[g] => student
[s] => teacher
[f] => tree
)
 
备注：按值升序排序

6.arsort(); 按照键值对关联数组进行降序排序。

1 <?php
2 $arr=['c'=>'apple', 'f'=>'tree', 'a'=>'father', 's'=>'teacher', 'g'=>'student',];
3 arsort($arr);
4 print_r($arr);
5 ?>

结果输出：

Array
(
[s] => teacher
[g] => student
[f] => tree
[c] => apple
[a] => father
)

 
备注：按值降序排序

7.array_muiltsort(); 对多个数组或多维数组进行排序。

array_multisort ( array &$array1 [, mixed $array1_sort_order = SORT_ASC [, mixed $array1_sort_flags = SORT_REGULAR [, mixed $... ]]] )

<?php
$arr4 = [
    [1,2,3,4,5],
    ['a'=>'father','f'=>'before','d'=>'apple','e'=>'six'],
    [1=>'master','b'=>18,2=>5,'a'=>'admin']
];

array_multisort($arr4);

print_r($arr4);


输出结果：

Array
(
[0] => Array
(
[a] => father
[f] => before
[d] => apple
[e] => six
)

[1] => Array
(
[1] => master
[b] => 18
[2] => 5
[a] => admin
)

[2] => Array
(
[0] => 1
[1] => 2
[2] => 3
[3] => 4
[4] => 5
)

)


文档使用详解：https://www.php.net/manual/zh/function.array-multisort.php

8.natcasesort(); 用“自然排序”算法对数组进行不区分大小写字母的排序。

natcasesort ( array &$array ) : bool

1 <?php
2 
3 $arr = ['c'=>'apple', 'f'=>'tree', 'a'=>'father', 's'=>'teacher', 'g'=>'student',];
4 natcasesort($arr);
5 
6 print_r($arr);



输出结果：
Array
(
[c] => apple
[a] => father
[g] => student
[s] => teacher
[f] => tree
)

二、

8.shuffle(); 打乱数组。

shuffle ( array &$array ) : bool

<?php


$arr = [1,2,3,4,5,6,7,8,9,10];

shuffle($arr);

print_r($arr);



输出结果：
Array
(
[0] => 7
[1] => 6
[2] => 10
[3] => 1
[4] => 3
[5] => 9
[6] => 8
[7] => 4
[8] => 5
[9] => 2
)

9.array_rand(); 从数组中取出一个或多个随机的单元，并返回随机条目的一个或多个键。

array_rand ( array $array [, int $num = 1 ] ) : mixed

<?php

$arr =['a'=>1,'b'=>2,'c'=>3,'d'=>4,'e'=>5,'f'=>6,'g'=>7,'h'=>8,'i'=>9,'j'=>10];

$keys = array_rand($arr,3);

$keys = array_rand($arr3,3);
print_r($keys);

foreach( $keys as $v){
    echo $arr3[$v];
    echo "
";
}


输出结果：
Array
(
[0] => b
[1] => c
[2] => f
)
2
3
6