PHP string reversal questions often encountered in interviews

This video explains PHP string reversal, a problem often encountered in interviews.

1. Single-byte string reversal

php提供了用于字符串反转的函数strrev() $str = 'abcdef'; echo strrev($str); 2.对于包含中文的多字节字符串需要用到mb_substr() $str = '字符串反转'; function rev($str, $encoding = 'utf-8'){ $len = mb_strlen($str); $result = ''; for ($i = $len-1; $i>=0; $i--){ $result.= mb_substr($str,$i,1,$encoding); } return $result; } echo rev($str) 3.算法实现 首位交换 $str = 'abcdefg'; $len = strlen($str); $times = $len/2; for($i = 0;$i <= $times; $i++ ){ $tmp = $str[$i]; $str[$i] = $str[$len-$i-1]; $str[$len-$i-1] = $tmp; } echo $str;

This film explains the php string reversal of problems often encountered in interviews. For more related knowledge, please pay attention to the php Chinese website.

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