结论:用加号合并数组: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;
用array_merge()合并数组: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
第一先看数组元素:
<?php $a = array('r'=>1,2,3,4); var_dump('a',$a); $b = array('r'=>5,6,7,8); var_dump('b',$b); $c = array('r'=>5,6,7,8,9); var_dump('c',$c); var_dump('a+b',$a+$b); var_dump('a+c', $a+$c); var_dump('amb', array_merge($a, $b)); var_dump('amc', array_merge($a, $c));
第二看输出:
string 'a' (length=1) array 'r' => int 1 0 => int 2 1 => int 3 2 => int 4 string 'b' (length=1) array 'r' => int 5 0 => int 6 1 => int 7 2 => int 8 string 'c' (length=1) array 'r' => int 5 0 => int 6 1 => int 7 2 => int 8 3 => int 9 string 'a+b' (length=3) array 'r' => int 1 0 => int 2 1 => int 3 2 => int 4 string 'a+c' (length=3) array 'r' => int 1 0 => int 2 1 => int 3 2 => int 4 3 => int 9 string 'amb' (length=3) array 'r' => int 5 0 => int 2 1 => int 3 2 => int 4 3 => int 6 4 => int 7 5 => int 8 string 'amc' (length=3) array 'r' => int 5 0 => int 2 1 => int 3 2 => int 4 3 => int 6 4 => int 7 5 => int 8 6 => int 9
