``` php 双引号字符串里包变量的用法 第一种 $ary['a'] 去掉单引号 $ary = array('a'=>1); $b = 5; $str = "fdsfdsf$ary[a]"; $str = "fdsfdsf$b"; echo $str; 第二种 用花括号包起来 $ary = array('a'=>1); $b = 5; $str = "fdsfdsf{$ary['a']}"; $str = "fdsfdsf$b"; echo $str; ```