Common string and file operation questions during PHP interviews

Common string and file operation questions in PHP interviews PHP flip Chinese string PHP calculate URL file suffix HP calculate the relative path of two files HP traverse all files and folders in the directory Full range of PHP Video Tutorial: elaborate PHP-http://www.xishuophp.com/

1. PHP flip Chinese Strings

Function reverse ($ str) {$ r = array (); for ($ I = 0; $ I <mb_strlen ($ str); $ I ++) {$ r [] = mb_substr ($ str, $ I, 1, 'utf-8');} return implode (array_reverse ($ r ));} echo reverse ('www .phpha.com PHP blog'); // Result: 'Weibo PHP Zhutian moc. ahphp. wwww'

2. PHP calculates the URL file suffix

Function getext ($ url) {$ data = parse_url ($ url); $ path = $ data ['path']; $ info = pathinfo ($ path ); return $ info ['extension'];} echo getext ('http: // blog.phpha.com/archives/1670.html? Id = 1670 '); // Result: 'html'

3. PHP calculates the relative path of the two files

Function getrpath ($ path, $ conpath) {$ pathArr = explode ('/', $ path); $ conpathArr = explode ('/', $ conpath ); $ dismatchlen = 0; for ($ I = 0; $ I <count ($ pathArr); $ I ++) {if ($ conpathArr [$ I]! = $ PathArr [$ I]) {$ dismatchlen = count ($ pathArr)-$ I; $ arrleft = array_slice ($ pathArr, $ I); break ;}} return str_repeat ('.. /', $ dismatchlen ). implode ('/', $ arrleft);} $ a = '/a/B/c/d/e. php '; $ B ='/a/B/12/34/5. php '; echo getrpath ($ a, $ B); // Result :'.. /.. /.. /c/d/e. php'

4. PHP traverses all files and folders in the directory

Function finddir ($ dir) {$ files = array (); if (is_dir ($ dir) {if ($ handle = opendir ($ dir )) {while ($ file = readdir ($ handle ))! = False) {if ($ file! = '.' & $ File! = '.. ') {If (is_dir (rtrim ($ dir ,'/'). '/'. $ file) {$ files [$ file] = finddir (rtrim ($ dir ,'/'). '/'. $ file);} else {$ files [] = rtrim ($ dir ,'/'). '/'. $ file ;}}closedir ($ handle) ;}return $ files ;}print_r (finddir ('F:/Golang/src ');/** result: array ([0] => F:/Golang/src/hello. go [1] => F:/Golang/src/src.exe [test] => Array ([0] => F:/Golang/src/test/sss.txt )) **/