Can someone please explain what the following regular expression means?
^(?=.*[\p{L}\p{M}0-9]).{6,50}$
It forces users to have at least one number in their username.
How should I modify it to remove this constraint?
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1 Answer
You need to remove the 0-9 constraint set in the look-ahead:
^(?=.*[\p{L}\p{M}]).{6,50}$
Now, it allows a string containing any symbols but a newline, from 6 to 50 occurrences, and at least one Unicode letter.
To use it in Java, you need to double-escape backslashes:
String pattern = "^(?=.*[\\p{L}\\p{M}]).{6,50}$";
answered May 15, 2015 at 12:19
Wiktor Stribiżew
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4 Comments
Wiktor Stribiżew
What language/tool are you using?
Mahdi
This is a web application written in Java.
Wiktor Stribiżew
Java regex is better tested at regexplanet.com, or in the IDE. Here is a demo of what the regex validates in PCRE (it is similar to Java flavor): regex101.com/r/oW0iY2/1. As you see, there must be at least 6 and up to 50 characters and there must be at least 1 letter inside. Also, you must remember that in Java, you need to use double backslashes:
String pattern = "^(?=.*[\\p{L}\\p{M}]).{6,50}$";