line.matches("[A-Z] ([a-zA-z][a-zA-Z]*)|\\#")
I need to read elements like
"A ddg", "B gH" or "D #"
But it doesn't work and I need to know if the regular expression is ok.
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Your explanation is not clear. Which phrases are you trying to "catch" exactly? That can help understand what you are trying to achieve. Be more specific.Shahar– Shahar2015-01-10 21:38:09 +00:00Commented Jan 10, 2015 at 21:38
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What do you mean by "I need to read elements like..."? Do you want to find them in your line, or do you want to check if entire line is element which can be matched by this regex?Pshemo– Pshemo2015-01-10 21:42:08 +00:00Commented Jan 10, 2015 at 21:42
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I want to check if entire line is element which can be matched by this regexbulinecolorate– bulinecolorate2015-01-10 21:46:38 +00:00Commented Jan 10, 2015 at 21:46
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3 Answers
Try this:
line.matches("[A-Z] ([a-zA-Z]+|#)")
Much of your regex is redundant:
\\#is the same as#- there's nothing special about#[a-zA-Z][a-zA-Z]*is identical to[a-zA-Z]+
The thing you were missing was the correct alternation - you didn't have the closing bracket in the right place.
Comments
You have this problems:
- you closed your parenthesis too early, which placed
#outside of it, - you used
A-zrange instead ofA-Z.
Also you can improve your regex a little:
- you don't need to escape
# - instead of
xx*you can usex+since:+represents once or more*represents zero or more
So try with
line.matches("[A-Z] ([a-zA-Z]+|#)")
Comments
This will work:
line.matches("[A-Z]( [a-zA-z]+)?( #)?")
What will match (examples):
A
A #
A a
A aAaA
A a #
A aAaAa #
If you don't want "A #":
line.matches("[A-Z]( [a-zA-z]+| #)")
4 Comments
bulinecolorate
The left side(before space) is uppercase(just one character) and the right side is uppercase or/and lowercase or just #(it can be "A aa" or "B #" but no "A aa#")
MightyPork
Yes, that's correct. Not really sure what you wanted. Edit the question with examples if you think my solution is wrong.
Bohemian
FYI the leading/trailing ^ and $ are redundant. See javadoc of matches() for why
MightyPork
ah okay, just wanted to be sure. removed.
