Error use php preg_match not match string

Question

I need get string follow this format (C-001 and C-001-C)

C-001 (match)
C-002C (not match)
C-003-C (match)
D-004 (not match)

This is my code

if(preg_match("/^C-[0-9]$/", $input_line, $output_array)) {
    print_r($output_array);
} else {
    echo "NOT MATCH";
}

But result show 3 string (C-001, C-002C, C-003-C), C-002C is wrong, how to fix it?

Answer 1

In your current regex you are looking for C- followed by 1 digit. If you want 3 digits you should use [0-9]{3}

^C-[0-9]{3}$

If you want to also allow another -C you can use (-C)? (the question mark is there as an optional group:

^C-[0-9]{3}(-C)?$

Here is a working example:
https://regex101.com/r/0JHN43/1

And this one is inside the preg_match block you have:

if(preg_match("/^C-[0-9]{3}(-C)?$/", $input_line, $output_array)) {