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Regular Expressions

Hi,

I have several regular expressions that I need to run against
documents. Is it possible to combine several expressions in one
expression in Regex object. So that it is faster, or will I have to
use all the expressions seperately?

Here are my regular expressions that check for valid email address and
link
Dim Expression As String =
"([\w\-]+\.)*[\w\-]+@([\w\-]+\.)+([\w\-]{2,5})"
EmailRegex = New Regex(Expressio n, RegexOptions.Ig noreCase Or
RegexOptions.Co mpiled)

Dim HrefPattern As String =
"href\s*=\s*(?: ""(?<match>[^""]*)""|(?<match>\ S+))"
HrefRegex = New Regex(HrefPatte rn, RegexOptions.Ig noreCase Or
RegexOptions.Co mpiled)

so can I combine both regular expressions in one?

Thanks
Nov 20 '05 #1
2 5087
Sehboo,
Using Alternation you can combine regular expressions.

Dim regex As New Regex(Expressio n & "|" & HrefPattern,
RegexOptions.Ig noreCase Or
RegexOptions.Co mpiled)
You may want to also use a grouping construct with a name so you know which
expression you matched...

Also you may want to use Match & NextMatch to walk the matches found,
however I do not have a good example of this...
I find both of the following sites invaluable when working with regular
expressions.

A tutorial & reference on using regular expressions:
http://www.regular-expressions.info/

The MSDN's documentation on regular expressions:
http://msdn.microsoft.com/library/de...geElements.asp

Hope this helps
Jay

"Sehboo" <ma*********@ho tmail.com> wrote in message
news:7b******** *************** ***@posting.goo gle.com... Hi,

I have several regular expressions that I need to run against
documents. Is it possible to combine several expressions in one
expression in Regex object. So that it is faster, or will I have to
use all the expressions seperately?

Here are my regular expressions that check for valid email address and
link
Dim Expression As String =
"([\w\-]+\.)*[\w\-]+@([\w\-]+\.)+([\w\-]{2,5})"
EmailRegex = New Regex(Expressio n, RegexOptions.Ig noreCase Or
RegexOptions.Co mpiled)

Dim HrefPattern As String =
"href\s*=\s*(?: ""(?<match>[^""]*)""|(?<match>\ S+))"
HrefRegex = New Regex(HrefPatte rn, RegexOptions.Ig noreCase Or
RegexOptions.Co mpiled)

so can I combine both regular expressions in one?

Thanks

Nov 20 '05 #2
Sehboo,
Using Alternation you can combine regular expressions.

Dim regex As New Regex(Expressio n & "|" & HrefPattern,
RegexOptions.Ig noreCase Or
RegexOptions.Co mpiled)
You may want to also use a grouping construct with a name so you know which
expression you matched...

Also you may want to use Match & NextMatch to walk the matches found,
however I do not have a good example of this...
I find both of the following sites invaluable when working with regular
expressions.

A tutorial & reference on using regular expressions:
http://www.regular-expressions.info/

The MSDN's documentation on regular expressions:
http://msdn.microsoft.com/library/de...geElements.asp

Hope this helps
Jay

"Sehboo" <ma*********@ho tmail.com> wrote in message
news:7b******** *************** ***@posting.goo gle.com... Hi,

I have several regular expressions that I need to run against
documents. Is it possible to combine several expressions in one
expression in Regex object. So that it is faster, or will I have to
use all the expressions seperately?

Here are my regular expressions that check for valid email address and
link
Dim Expression As String =
"([\w\-]+\.)*[\w\-]+@([\w\-]+\.)+([\w\-]{2,5})"
EmailRegex = New Regex(Expressio n, RegexOptions.Ig noreCase Or
RegexOptions.Co mpiled)

Dim HrefPattern As String =
"href\s*=\s*(?: ""(?<match>[^""]*)""|(?<match>\ S+))"
HrefRegex = New Regex(HrefPatte rn, RegexOptions.Ig noreCase Or
RegexOptions.Co mpiled)

so can I combine both regular expressions in one?

Thanks

Nov 20 '05 #3

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