array_merge和+号合并数组的区别

先看栗子:

array_merge

$a = [51 => 12345];$b = [10 => 5678];$c = [];$c = array_merge($c,$a,$b); // Array ( [0] => 12345 [1] => 5678 )

$a = [51 => 12345];$b = [51 => 5678];$c = [];$c = array_merge($c,$a,$b); print_r($c); // Array ( [0] => 12345 [1] => 5678 )

$a = ['aa' => 12345];$b = ['aa' => 5678];$c = [];$c = array_merge($c,$a,$b); print_r($c);// Array ( [aa] => 5678 )

值覆盖情况: 只考虑字符串索引的键值对, 用后边数组的值覆盖掉前面数组中键名相同的值

数字索引的值则不覆盖,同时保留

另外: array_merge()会重排两个数组的数字索引,+则不会。

+号

$a = [51 => 12345];$b = [10 => 5678];$c = [];$C = $a+$b; // Array ( [51] => 12345 [10] => 5678 )

$a = [51 => 12345];$b = [51 => 5678];$c = [];$c = $a+$b; print_r($c); // Array ( [51] => 12345 )

$a = ['aa' => 12345];$b = ['aa' => 5678];$c = [];$c = $a+$b; print_r($c);// Array ( [aa] => 12345 )

值覆盖情况: 既考虑数字索引的键值对,也考虑字符串索引的键值对, 用前边数组的值覆盖后边的键名相同的值.