PHP几个比较常见的面试程序题整理

	//反转字符串	function mb_strrev($str){		$len = mb_strlen($str,'utf-8');		$r = array();		for($i=0;$i<$len;$i++){			$r[] = mb_substr($str,$i,1,'utf-8');		}		return implode(array_reverse($r));	}

	//得到url中扩展名	function getUrlExt($str){		$url_info = parse_url($str);		if(array_key_exists('path',$url_info)){			$path = $url_info['path'];			$file_info = pathinfo($path);			if(array_key_exists('extension',$file_info)){				return $file_info['extension'];			}		}		return false;		}

	function getrpath($path,$conpath){		$pathArr = explode('/',$path);		$conpathArr = explode('/',$conpath);		//$dis_match_len = 0;		for($i=0;$i<count($pathArr);$i++){			if($pathArr[$i] != $conpathArr[$i]){				$dis_match_len = count($pathArr) - $i - 1;				$arr_left = array_slice($pathArr,$i);				break;			}		}		return str_repeat('../',$dis_match_len).implode('/',$arr_left);	}

	function getrpath2($path,$conpath){		$pathA = explode('/',$path);		$pathB = explode('/',$conpath);		$res = array_diff_assoc($pathA,$pathB);		$path = '';		for($i=0;$i<count($res)-1;$i++){			$path .= '../';		}		$path .= implode('/',$res);		return $path;	}