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The role of PHP curly braces
When the PHP parser encounters a dollar ($) symbol, he Like many other parsers, it will combine as many identifiers as possible to form a legal variable name.
You can use curly braces to clarify the boundaries of variables and enclose the variables as a whole for parsing
You can use {curly brackets} to add, delete, modify, and query specified characters in the string
characters The string starts from 0
You can use [square brackets] to achieve the same operation
Operation relative to an array
$str = 'abcd'; echo $str{0}; //输出$str中下标为0的 a$str{1} = 'z'; //将下标为1的b替换成z,(注意:一次只能替换一个字符)
Replacing the characters with empty characters is equivalent to the delete operation
$str = 'asdasldjasljfas'; echo $str{mt_rand(0,strlen($str)-1)}; //随机取一个字符 mt_rand(0,10) //在0-10中间随机取一个 strlen($str) //计算这个变量的长度
in the interview
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