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pattern matching only alphabetic characters

Radtherapist
Novice

Apr 2, 2009, 5:20 PM

Post #1 of 8 (1672 views)

pattern matching only alphabetic characters	Can't Post

I am trying to match only alphabetic characters, but I can't work out the expression to use in the match.

I have tried:

\b\D\b,

\b\D*\b

\b[a-z][A-Z]\b

plus a few others. But when I try to match something like "aa3" I get a match. I can see that it would pick up the a's, and therefore match. How does one make it not match if there is a number or special character in the mix?

I know there is an OR symbol (|), but is there an AND symbol. My thoughts are if I can do something like [^0-9] AND ([a-z]|[A-Z]), that this might work. Any comments are appreciated.

Regards

Vincent

KevinR
Veteran

Apr 2, 2009, 7:43 PM

Post #2 of 8 (1670 views)

Re: [Radtherapist] pattern matching only alphabetic characters [In reply to]	Can't Post

Your explanation is a bit all over the place. If you want to match alpha-numeric stuff you can use \w which is a short cut character class for: a-zA-Z0-9_ or you can use: [a-zA-Z0-9] if you don't want the underscore included. Some sample data might help and a clearer explanation of what you are trying to match.
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Radtherapist
Novice

Apr 2, 2009, 9:02 PM

Post #3 of 8 (1668 views)

Re: [KevinR] pattern matching only alphabetic characters [In reply to]	Can't Post

Hi,

I was after something to test this:

does aaabbb9 only have only alphabet characters - no numbers - no match

BBBAAA - match

aA7Ba -no match

5aaaBBB - no match

I am wanting to ensure a string of characters does not contain numbers.

Vince

Tumata
User

Apr 2, 2009, 11:07 PM

Post #4 of 8 (1662 views)

Re: [Radtherapist] pattern matching only alphabetic characters [In reply to]	Can't Post

Hi, Vince. Try this script:

Code

#!/usr/bin/perl 
 
local $_ = "aA3Bb"; 
 
if ( m/\d/ ) { 
    print 'Conntains numbers'; 
} else { 
    print 'Doesn\'t contain numbers'; 
}

Radtherapist
Novice

Apr 3, 2009, 1:26 AM

Post #5 of 8 (1656 views)

Re: [Tumata] pattern matching only alphabetic characters [In reply to]	Can't Post

Thanks Tumata,

I can see this would work.

Does this do the same sort of thing, but only looking for the alphabet characters only instead of numeric:

^[a-zA-Z]*$

Vince

Tumata
User

Apr 3, 2009, 1:53 AM

Post #6 of 8 (1655 views)

Re: [Radtherapist] pattern matching only alphabetic characters [In reply to]	Can't Post

Yes. All strings that contains only letters will match this pattern. Empty strings will also match Smile

KevinR
Veteran

Apr 3, 2009, 9:48 AM

Post #7 of 8 (1646 views)

Re: [Radtherapist] pattern matching only alphabetic characters [In reply to]	Can't Post

In Reply To

Thanks Tumata,

I can see this would work.

Does this do the same sort of thing, but only looking for the alphabet characters only instead of numeric:

^[a-zA-Z]*$

Vince

It does the same thing but Tumatas code would be more efficient. Keep in mind, as he said, yours, and his, can allow empty strings to match successfully. If you don't want that behavior change the * quantifier to + in your regexp.
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Radtherapist
Novice

Apr 3, 2009, 7:44 PM

Post #8 of 8 (1642 views)

Re: [KevinR] pattern matching only alphabetic characters [In reply to]	Can't Post

Many thanks to both.

Vince

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