Question

To validate names that can be

John, John Paul, etc.

I use this regex:

String regex = "[A-Z]([a-z]+|\\s[a-z]+)";

but when I do:

boolean ok = Pattern.matches(regex, "John Paul");

the matches fail?

Why? I want to use matches to validate the string as whole…

Is that regex wrong?

Answer 1

Try something like this:

[A-Z][a-z]+( [A-Z][a-z]+)?

The ? is an optional part that matches the last name. This captures the last name (with a preceding space) in group 1. You can use a non-capturing group (?:...) if you don’t need this capture.

References

• regular-expressions.info – Question Mark for Optional

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Problem with original pattern

Here’s the original pattern:

[A-Z]([a-z]+|\s[a-z]+)

Expanding the alternation this matches:

[A-Z][a-z]+

Or:

[A-Z]\s[a-z]+

This does match John, and J paul, but it clearly doesn’t match John Paul.