Php generates a random string containing numbers, uppercase and lowercase English letters-PHP source code

Php generates a random string containing numbers, uppercase and lowercase English letters. php code

/*** Generate a random string of the specified length (including uppercase letters, lowercase letters, and numbers) ** @ author Wu Junwei ** @ param int $ length the length of the string to be generated * @ return string contains a random string of uppercase and lowercase English letters and numbers */function random_str ($ length) {// generate an array containing uppercase English letters, lowercase English letters, and numbers $ arr = array_merge (range (0, 9), range ('A', 'z '), range ('A', 'z'); $ str = ''; $ arr_len = count ($ arr); for ($ I = 0; $ I <$ length; $ I ++) {$ rand = mt_rand (0, $ arr_len-1); $ str. = $ arr [$ rand];} return $ str ;}