PHP regular matches 6 to 16 character combinations (and can only be numbers, letters, and underscores)

This article introduces how to use PHP regular rules to match 6-digit and 16-digit character combinations. This regular rule requires only numbers, letters, and underscores. Friends in need can refer to it.

Requirements: PHP regular matches strings with 6 to 16 characters. Only 6 to 16 characters consisting of numbers, letters, and underscores are allowed. True is returned if applicable, otherwise false is returned.

Answer: From 6 to 16 digits, the regular expression can be written like this: {6,16}. The regular expression for any character from 6 to 16 bits is as follows: .{6,16} Only combinations of numbers, letters, and underscores are allowed. The regular rule is: [0-9_a-zA-Z] Put it together, the complete regex is:

^[_0-9a-z]{6,16}$

The following is an example of applying this regular verification password.

<?php
/**
* php正则验证密码规则
* 只允许 数字、字母、下划线
* 最短6位、最长16位
* 搜集整理：bbs.it-home.org
*/
function ispassword($str) {
 if (preg_match('/^[_0-9a-z]{6,16}$/i',$str)){
  return true;
 }else {
  return false;
 }
}
$password = 'abcde@';
if(ispassword($password)) {
 echo '符合';
}else {
 echo '不符合';
}
//output  不符合

echo '<br>';
$password = 'abcdeasdas_1324';
if(ispassword($password)) {
 echo '符合';
}else {
 echo '不符合';
}
//output  符合
?>