如何以这种方式编写javascript Regex它接受6个字符

Question

Javascript正则表达式验证它包含6个字符，其中一个字符（1）应该是一个数字。

var pwdregex  =/^[A-Za-z1-9]{6}$/;

Answer 1

This will guarantee exactly one number (ie a non-zero decimal digit):

var pwdregex = /^(?=.{6}$)[A-Za-z]*[1-9][A-Za-z]*$/;

And this will guarantee one or more consecutive number:

var pwdregex = /^(?=.{6}$)[A-Za-z]*[1-9]+[A-Za-z]*$/;

And this will guarantee one or more not-necessarily-consecutive number:

var pwdregex = /^(?=.{6}$)[A-Za-z]*(?:[1-9][A-Za-z]*)+$/;

All of the above expressions require exactly six characters total. If the requirement is six or more characters, change the {6} to {6,} (or remove the $ from {6}$ ).

Answer 2

All possible combinations of 1 digit and alphanumeric chars with a length of 6.

if (subject.match(/^[a-z]{0,5}\d[a-z]{0,5}$/i) && subject.length == 6) {
    // Successful match
} else {
    // Match attempt failed
}

Answer 3

[Edit] Fixed obvious bug...

If you are ok with using a function instead of a regex you can do this:

var sixAlphaOneDigit = function(s) {
  return !!((s.length==6) && s.replace(/\d/,'').match(/^[A-Za-z]{5}$/));
};

sixAlphaOneDigit('1ABCDE'); // => true
sixAlphaOneDigit('ABC1DE'); // => true
sixAlphaOneDigit('ABCDE1'); // => true
sixAlphaOneDigit('ABCDE'); // => false
sixAlphaOneDigit('ABCDEF'); // => false
sixAlphaOneDigit('ABCDEFG'); // => false

If you want to do it strictly in a regex then you could build a terribly long pattern which enumerates all possibilities of the position of the digit and the surrounding (or leading, or following) characters.