I need a regular expression which matches lines with only 4(four) hyphens and 13 digits(0-9). The order is undefined. I have regex like:
^([0-9\u2013-]{17})$
But, when I receive strings as
----123456789---- or 1-2-3-4-5-6-7-8-9
matching is true but it must be false for me.
Could you please explain what I need use in order to matches were only with strings like 123-345-565-45-67 or 123-1-34-5435-45- or ----1234567890123 etc?
Try this regex:
^(?=(?:[^-]*-){4}[^-]*$)(?=(?:\D*\d){13}\D*$).*$
Explanation:
^ - asserts the start of the line(?=(?:[^-]*-){4}[^-]*$) - positive lookahead to make sure that there are only 4 occurrences of - present in the string(?=(?:\D*\d){13}\D*$) - positive lookahead to make sure that there are 13 occurrences of a digit present in the string.* - once the above 2 lookaheads are satisified, match 0+ occurrences of any character except a newline character$ - asserts the end of the lineEscape \ with another \ in JAVA