PHP中array_merge合并两个数组的程序
合并数据在php中我们利用array_merge()函数来实现,array_merge() 函数把两个或多个数组合并为一个数组. 如果键名有重复,该键的键值为最后一个键名对应的值（后面的覆盖前面的）.如果数组是数字索引的,则键名会以连续方式重新索引.
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 )1）键名为数字时,array_merge()不会覆盖掉原来的值,但＋合并数组则会把最先出现的值作为最终结果返回,而把后面的数组拥有相同键名的那些值[抛弃]掉（不是覆盖）
2）键名为字符时,＋仍然把最先出现的值作为最终结果返回,而把后面的数组拥有相同键名的那些值[抛弃]掉,但array_merge()此时会覆盖掉前面相同键名的值
注释:如果仅仅向 array_merge() 函数输入了一个数组,且键名是整数,则该函数将返回带有整数键名的新数组,其键名以 0 开始进行重新索引
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