5_PHP数组_3_数组处理函数及其应用_9_数组集合运算函数

以下为学习孔祥盛主编的《PHP编程基础与实例教程》（第二版）所做的笔记。

数组集合运算函数

1. array_merge() 函数

程序：

<?php
$array1 = array("color"=>"red",2,4);
$array2 = array("a","b","color"=>"green","shape"=>"trapezoid",4);
$result = array_merge($array1,$array2);　　//并集
print_r($result);
//Array ( [color] => green [0] => 2 [1] => 4 [2] => a [3] => b [shape] => trapezoid [4] => 4 )
?>

输出：

Array ( [color] => green [0] => 2 [1] => 4 [2] => a [3] => b [shape] => trapezoid [4] => 4 )

2. array_diff() 函数

程序：

<?php
$array1 = array("color"=>"red",2,4);
$array2 = array("color"=>"red",2);
$result = array_diff($array1,$array2);　　//值的差集
print_r($result);   //Array ( [1] => 4 )
?>

输出：

Array ( [1] => 4 )

3. array_intersect() 函数

程序：

<?php
$array1 = array("color"=>"red",2,4);
$array2 = array("color"=>"red",2);
$result = array_intersect($array1,$array2);     //值的交集
print_r($result);   //Array ( [color] => red [0] => 2 )
?>

输出：

Array ( [color] => red [0] => 2 )

4. array_diff_assoc() 函数

程序：

<?php
$array1 = array("a"=>"apple",'c'=>"cat",1,2);
$array2 = array("b"=>"apple",'c'=>'cat',"1");
$result = array_diff_assoc($array1,$array2);    //差集
print_r($result);   //Array ( [a] => apple [1] => 2 )
?>

输出：

Array ( [a] => apple [1] => 2 )

5. array_intersect_assoc() 函数

程序：

<?php
$array1 = array("a"=>"apple",'c'=>"cat",1,2);
$array2 = array("b"=>"apple",'c'=>'cat',"1");
$result = array_intersect_assoc($array1,$array2);    //交集
print_r($result);   //Array ( [c] => cat [0] => 1 )
?>

输出：

Array ( [c] => cat [0] => 1 )

6. array_diff_key() 函数

程序：

<?php
$array1 = array("a"=>"apple",1,"c"=>"cat",2);
$array2 = array("a"=>"banana","c"=>'cat',"1");
$result = array_diff_key($array1,$array2);    //键的差集
print_r($result);   //Array ( [1] => 2 )
?>

输出：

Array ( [1] => 2 )

7. array_intersect_key() 函数

程序：

<?php
$array1 = array("a"=>"apple",'c'=>"cat",2);
$array2 = array("a"=>"banana",'c'=>'cat',"1");
$result = array_intersect_key($array1,$array2);    //键的交集
print_r($result);   //Array ( [a] => apple [c] => cat [0] => 2 )
?>

输出：

Array ( [a] => apple [c] => cat [0] => 2 )