hyphen in regular expression (cSharp)

  • Thread starter Thread starter jayanthigk2004
  • Start date Start date
J

jayanthigk2004

Input
a-

Patterns

\w*-*
\w*(-*)
\w*(-)*
\w*[-]*

No of the patterns results in a match. Tried escaps(\) before hyphen
still no match.

My requirement is to make sure a string contains only digits, alphabets
and hypen (each 0 or more times).
 
Well, you're not being very specific about your requirements, but the
following would work with them as you have stated them:

[\w-]*

Translated: Match any combination of 0 or more of digits, alphabetical
characters, or hyphens.

--
HTH,

Kevin Spencer
Microsoft MVP
Computer Control Freak
http://unclechutney.blogspot.com

A man, a plan, a canal, a palindrome that has.. oh, never mind.
 
I would think all of those patterns result in matches. Could it be some
mistake in your code?
 
The patterns would certainly match "a-" but not the requirements he posted.
It is a matter of sequence. The regular expression:

\w*-*

literally means "a match is zero or more word characters *followed by* zero
or more hyphen characters. So, the string "-a" would result in 2 matches,
one for the "-" and one for the "a", while the regular expression:

[\w-]*

literally means "a match is any combination 0 or more of word characters
and/or hypens, so that the string "-a" would result in a single match
containing both characters.

--
HTH,

Kevin Spencer
Microsoft MVP
Chicken Salad Shooter
http://unclechutney.blogspot.com

A man, a plan, a canal, a palindrome that has.. oh, never mind.

Truong Hong Thi said:
I would think all of those patterns result in matches. Could it be some
mistake in your code?

Input
a-

Patterns

\w*-*
\w*(-*)
\w*(-)*
\w*[-]*

No of the patterns results in a match. Tried escaps(\) before hyphen
still no match.

My requirement is to make sure a string contains only digits, alphabets
and hypen (each 0 or more times).
Click to expand...
Click to expand...
 
My requirement is for validation and it should allow only digits,
alphabets and hyphens in the text the user enters.

Thanks

Kevin said:
The patterns would certainly match "a-" but not the requirements he posted.
It is a matter of sequence. The regular expression:

\w*-*

literally means "a match is zero or more word characters *followed by* zero
or more hyphen characters. So, the string "-a" would result in 2 matches,
one for the "-" and one for the "a", while the regular expression:

[\w-]*

literally means "a match is any combination 0 or more of word characters
and/or hypens, so that the string "-a" would result in a single match
containing both characters.

--
HTH,

Kevin Spencer
Microsoft MVP
Chicken Salad Shooter
http://unclechutney.blogspot.com

A man, a plan, a canal, a palindrome that has.. oh, never mind.

Truong Hong Thi said:
I would think all of those patterns result in matches. Could it be some
mistake in your code?

Input
a-

Patterns

\w*-*
\w*(-*)
\w*(-)*
\w*[-]*

No of the patterns results in a match. Tried escaps(\) before hyphen
still no match.

My requirement is to make sure a string contains only digits, alphabets
and hypen (each 0 or more times).
Click to expand...
Click to expand...
Click to expand...
 
I answered your question. See below.

--
HTH,

Kevin Spencer
Microsoft MVP
Chicken Salad Shooter
http://unclechutney.blogspot.com

A man, a plan, a canal, a palindrome that has.. oh, never mind.

My requirement is for validation and it should allow only digits,
alphabets and hyphens in the text the user enters.

Thanks

Kevin said:
The patterns would certainly match "a-" but not the requirements he
posted.
It is a matter of sequence. The regular expression:

\w*-*

literally means "a match is zero or more word characters *followed by*
zero
or more hyphen characters. So, the string "-a" would result in 2 matches,
one for the "-" and one for the "a", while the regular expression:

[\w-]*

literally means "a match is any combination 0 or more of word characters
and/or hypens, so that the string "-a" would result in a single match
containing both characters.

--
HTH,

Kevin Spencer
Microsoft MVP
Chicken Salad Shooter
http://unclechutney.blogspot.com

A man, a plan, a canal, a palindrome that has.. oh, never mind.

Truong Hong Thi said:
I would think all of those patterns result in matches. Could it be some
mistake in your code?

(e-mail address removed) wrote:
Input
a-

Patterns

\w*-*
\w*(-*)
\w*(-)*
\w*[-]*

No of the patterns results in a match. Tried escaps(\) before hyphen
still no match.

My requirement is to make sure a string contains only digits,
alphabets
and hypen (each 0 or more times).
Click to expand...
Click to expand...
Click to expand...
 
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