the following is my regex
regex: /^[a-zA-Z]+-.*(?=.*\d)(?=.*[a-zA-Z]).*-[0-9]+-[a-zA-Z]+-[0-9]+$/
the overall rules is: alphabet-alphanumeric-number-alphabet-number
im having problem at .*(?=.*\d)(?=.*[a-zA-Z]).*
the expected output for it to get a successful result for the alphanumeric part is
and fail if
but the result i get is all successful include the expected fail result
i see that using lookahead will also get the input after the dash(-) of the alphanumeric that caused it to be successful although it is not the expected result
You could try
^[a-zA-Z]+-(?![a-zA-Z]+-|\d+-)[a-zA-Z0-9]+-\d+-[a-zA-Z]+-\d+$
It uses this negative lookahead to check the second subsequence is not only made by alphabets or numerics
(?![a-zA-Z]+-|\d+-)
Alternatively, you can use this positive lookahead to check the second subsequence is made by a digit preceded any alphabets or the other way around
(?=[a-zA-Z]+\d|\d+[a-zA-Z])
It is important to use a lookahead to check it right at the start of the subsequence, and do not use .* in this situation since it might consume a - and checks the wrong sequence behind it.
You may check the test result here
For the alphanumeric part, you can assert not only digits till the next hyphen.
Using a case insensitive match:
^[a-z]+-(?!\d+-)[a-z]*\d[a-z\d]*-\d+-[a-z]+-\d+$
^ Start of string[a-z]+- Match 1+ chars a-z and -(?!\d+-) Negative lookahead, assert not only digits followed by -[a-z]*\d[a-z\d]*- Match optional chars a-z, match a digit and optional chars a-z or a digit\d+-[a-z]+-\d+ Match digits - chars a-z - digits$ End of stringconst regex = /^[a-z]+-(?!\d+-)[a-z]*\d[a-z\d]*-\d+-[a-z]+-\d+$/i;
[
"abc-abc-123-abc-123",
"abc-123-123-abc-123",
"abc-abcde-123-abc-123",
"abc-12345-123-abc-123",
"abc-ab23ca-123-abc-123",
"abc-1abc23-123-abc-123"
].forEach(s =>
console.log(`${s} --> ${regex.test(s)}`)
);why not:
/([A-Za-z]+[0-9]+|[0-9]+[A-Za-z]+)/
-- or --
/[A-Za-z]/.test(val) && /[0-9]/.test(val)
var cases = [
"abc123",
"123abc",
"1abc23",
"ab23ca",
// fail
"abcde",
"12345",
"abc-abc-123-abc-123", // not clear if these should fail?
"abc-123-123-abc-123"
];
cases.forEach(val => {
var ok = /([A-Za-z]+[0-9]+|[0-9]+[A-Za-z]+)/.test(val)
//var ok = /[A-Za-z]/.test(val) && /[0-9]/.test(val);
console.log(val, ok);
});