对数组的array_merge函数和+运算符比较迷惑,写了个小程序比较下发现了他们的不同. 特别是+运算符,他的意思是,将右边的数组单元(去重复)追加到左边数组的后面.
实例代码如下:
- <?php
- $arr1=array("a","b","c");
- $arr2=array("c","d","e");
- $myarray=array_merge($arr1,$arr2);
- print_r($myarray);
- $myarray=array_unique($myarray);
- print_r($myarray);
- ?>
实例代码如下:
- <?php
- $array1=array(1, 2);
- $array2=array(2, 3);
- $array3=array_merge($array1, $array2);
- $array3=array_unique($array3);
- ?>
实例代码如下:
- <?php
- echo "rn第一种情况rn";
- $a=array(1,2,3,4,5,6);
- $b=array(7,8,9);
-
- $c=array_merge ($a,$b);
- print_r($c);
- $c=$a+$b;
- print_r($c);
- $c=$b+$a;
- print_r($c);
-
-
- echo "rn第二种情况rn";
- $a=array('a','b','c','d','e','f');
- $b=array('a','x','y');
-
- $c=array_merge ($a,$b);
- print_r($c);
- $c=$a+$b;
- print_r($c);
- $c=$b+$a;
- print_r($c);
-
-
- echo "rn第三种情况rn";
-
- $a=array(
- 1=>'a',
- 2=>'b',
- 3=>'c',
- 4=>'d',
- 5=>'e',
- 6=>'f');
- $b=array(
- 1=>'a',
- 7=>'x',
- 8=>'y');
-
- $c=array_merge ($a,$b);
- print_r($c);
- $c=$a+$b;
- print_r($c);
- $c=$b+$a;
- print_r($c);
- ?>
结果如下:
- 第一种情况
-
- Array
-
- (
- [0] => 1
- [1] => 2
- [2] => 3
- [3] => 4
- [4] => 5
- [5] => 6
- [6] => 7
- [7] => 8
- [8] => 9
- )
- Array
-
- (
- [0] => 1
- [1] => 2
- [2] => 3
- [3] => 4
- [4] => 5
- [5] => 6
- )
- Array
-
- (
- [0] => 7
- [1] => 8
- [2] => 9
- [3] => 4
- [4] => 5
- [5] => 6
- )
-
- 第二种情况
-
- Array
-
- (
- [0] => a
- [1] => b
- [2] => c
- [3] => d
- [4] => e
- [5] => f
- [6] => a
- [7] => x
- [8] => y
- )
- Array
-
- (
- [0] => a
- [1] => b
- [2] => c
- [3] => d
- [4] => e
- [5] => f
- )
- Array
- (
- [0] => a
- [1] => x
- [2] => y
- [3] => d
- [4] => e
- [5] => f
- )
-
- 第三种情况
- Array
- (
- [0] => a
- [1] => b
- [2] => c
- [3] => d
- [4] => e
- [5] => f
- [6] => a
- [7] => x
- [8] => y
- )
- Array
- (
- [1] => a
- [2] => b
- [3] => c
- [4] => d
- [5] => e
- [6] => f
- [7] => x
- [8] => y
- )
- Array
- (
- [1] => a
- [7] => x
- [8] => y
- [2] => b
- [3] => c
- [4] => d
- [5] => e
- [6] => f
- )
拆分数组 array_slice()
array_slice()函数将返回数组中的一部分,从键offset开始,到offset+length位置结束.其形式:
Php代码
1.array array_slice (array array, int offset[,int length])
array array_slice (array array, int offset[,int length])
offset 为正值时,拆分将从距数组开头的offset 位置开始;如果offset 为负值,则拆分从距数组末尾的offset 位置开始.如果省略了可选参数length,则拆分将从offset 开始,一直到数组的最后一个元素.如果给出了length 且为正数,则会在距数组开头的offset+length 位置结束.相反,如果给出了length且为负数,则在距数组开头的count(input_array)-|length|位置结束.考虑一个例子:
Php代码
实例代码如下:
- <?php
- $fruits = array("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon", "Watermelon");
- $subset = array_slice($fruits, 3);
- print_r($subset);
-
-
- ?>
然后我们使用下负长度:
Php代码
实例代码如下:
- <?php
- $fruits = array("Apple", "Banana", "Orange", "Pear", "Grape", "Lemon", "Watermelon");
- $subset = array_slice($fruits, 2, -2);
- print_r($subset);
-
-
- ?>
(责任编辑:admin) |