By using this site, you agree to our updated Privacy Policy and our Terms of Use. Manage your Cookies Settings.
431,757 Members | 1,990 Online
Bytes IT Community
+ Ask a Question
Need help? Post your question and get tips & solutions from a community of 431,757 IT Pros & Developers. It's quick & easy.

Replace character

P: n/a
Hello,

I have a text as follows:

"My email is so*******@something.xyz and I posted this @ 2 am"

I need to replace the @ by (AT) bu only the ones that are in email
addresses.

All other @ shouldn't be replaced.

I know how to replace all @ but I am having problems in replacing only
the @'s in the email addresses.

How can I do this?

Thanks,
Miguel
Nov 20 '08 #1
Share this Question
Share on Google+
5 Replies


P: n/a
shapper wrote:
I have a text as follows:

"My email is so*******@something.xyz and I posted this @ 2 am"

I need to replace the @ by (AT) bu only the ones that are in email
addresses.

All other @ shouldn't be replaced.

I know how to replace all @ but I am having problems in replacing only
the @'s in the email addresses.

How can I do this?
Regex.Replace with a reasonable regex expression for
valid email addresses should give a reasonable correct
replacement.

Arne
Nov 20 '08 #2

P: n/a
On Nov 20, 2:33*am, Arne Vajhøj <a...@vajhoej.dkwrote:
shapper wrote:
I have a text as follows:
"My email is someth...@something.xyz and I posted this @ 2 am"
I need to replace the @ by (AT) bu only the ones that are in email
addresses.
All other @ shouldn't be replaced.
I know how to replace all @ but I am having problems in replacing only
the @'s in the email addresses.
How can I do this?

Regex.Replace with a reasonable regex expression for
valid email addresses should give a reasonable correct
replacement.

Arne
Hi,

I was trying that but I have two problems:
return Regex.Replace(text, "\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)
*", "(at)");

First I get a lot of errors on the pattern in each \ character:
Unrecognized escape sequence

The second problem is that this identifies all emails on my string but
I don't want to replace the emails but the @ in the emails.

Any idea?

Thanks,
Miguel
Nov 20 '08 #3

P: n/a
Hello shapper,
On Nov 20, 2:33 am, Arne Vajhøj <a...@vajhoej.dkwrote:
>shapper wrote:
>>I have a text as follows:

"My email is someth...@something.xyz and I posted this @ 2 am"

I need to replace the @ by (AT) bu only the ones that are in email
addresses.

All other @ shouldn't be replaced.

I know how to replace all @ but I am having problems in replacing
only the @'s in the email addresses.

How can I do this?
Regex.Replace with a reasonable regex expression for valid email
addresses should give a reasonable correct replacement.

Arne
Hi,

I was trying that but I have two problems:
return Regex.Replace(text, "\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)
*", "(at)");
First I get a lot of errors on the pattern in each \ character:
Unrecognized escape sequence

The second problem is that this identifies all emails on my string but
I don't want to replace the emails but the @ in the emails.

There are two options here: Either capture the first and second part of the
email in a group and put them back in.

Second, match only the @, but use lookahead and lookbehind constructions
to make sure you only replace the @ in an emailaddress

So here we go:

capture the first and last parts and replace:

(?<name>\w+([-+.]\w+)+)@(?<domain>\w+([-.]\w+)*\.\w+([-.]\w+)*))

and replace that with:

${name}(at)${domain}

This should be quite easy to understand. Capture the parts you want to keep
in a named group (?<name>..) and put them back into the replacement pattern
${name}.

The second option using look arounds:

(?<=\w+([-+.]\w+)+)(at)(?>\w+([-.]\w+)*\.\w+([-.]\w+)*))

and replace that with:

(at)

This one is usually harder to understand. (?<=...) looks back in your string
and tries to find the pattern that is defined at the '...'. If it cannot
find this exact pattern the whole expression fails.
(?>...) essentially does the same, but looks ahead, instead of backwards.
The funny thing is, that even though you search for something in your regex,
it doesn't become part of the actual Match and therefore doesn't get replaced.

Now to touch on your issue with th escape sequences. Any special character
sequence in regex starts with a \. And any escape sequence in C# code starts
with a \ as well, so if you put a regex in a string you again have two options:
First, escape all your \'s in your regex by putting an additional \ in front
of it. eg. \w becomes \\w. Second option is to use verbatim strings in C#
by placing an @ in front of the string definition like this: @"\w...more
regex goes here".

Hope this helps

--
Jesse Houwing
jesse.houwing at sogeti.nl
Nov 20 '08 #4

P: n/a
On Nov 20, 11:12*am, Jesse Houwing <jesse.houw...@newsgroup.nospam>
wrote:
Hello shapper,
On Nov 20, 2:33 am, Arne Vajhøj <a...@vajhoej.dkwrote:
shapper wrote:
>I have a text as follows:
>"My email is someth...@something.xyz and I posted this @ 2 am"
>I need to replace the @ by (AT) bu only the ones that are in email
addresses.
>All other @ shouldn't be replaced.
>I know how to replace all @ but I am having problems in replacing
only the @'s in the email addresses.
>How can I do this?
Regex.Replace with a reasonable regex expression for valid email
addresses should give a reasonable correct replacement.
Arne
Hi,
I was trying that but I have two problems:
return Regex.Replace(text, "\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)
*", "(at)");
First I get a lot of errors on the pattern in each \ character:
Unrecognized escape sequence
The second problem is that this identifies all emails on my string but
I don't want to replace the emails but the @ in the emails.

There are two options here: Either capture the first and second part of the
email in a group and put them back in.

Second, match only the @, but use lookahead and lookbehind constructions
to make sure you only replace the @ in an emailaddress

So here we go:

capture the first and last parts and replace:

(?<name>\w+([-+.]\w+)+)@(?<domain>\w+([-.]\w+)*\.\w+([-.]\w+)*))

and replace that with:

${name}(at)${domain}

This should be quite easy to understand. Capture the parts you want to keep
in a named group (?<name>..) and put them back into the replacement pattern
${name}.

The second option using look arounds:

(?<=\w+([-+.]\w+)+)(at)(?>\w+([-.]\w+)*\.\w+([-.]\w+)*))

and replace that with:

(at)

This one is usually harder to understand. (?<=...) looks back in your string
and tries to find the pattern that is defined at the '...'. If it cannot
find this exact pattern the whole expression fails.
(?>...) essentially does the same, but looks ahead, instead of backwards.
The funny thing is, that even though you search for something in your regex,
it doesn't become part of the actual Match and therefore doesn't get replaced.

Now to touch on your issue with th escape sequences. Any special character
sequence in regex starts with a \. And any escape sequence in C# code starts
with a \ as well, so if you put a regex in a string you again have two options:
First, escape all your \'s in your regex by putting an additional \ in front
of it. eg. \w becomes \\w. Second option is to use verbatim strings in C#
by placing an @ in front of the string definition like this: @"\w...more
regex goes here".

Hope this helps

--
Jesse Houwing
jesse.houwing at sogeti.nl
Hello,

I tried to use your code but in both expressions I get the error "to
many )'s".
I counted the ( and ) and removed the last ) in both expressions.

Now I don't get the error but the @ in the emails are not replaced.
This is what I have:

string a = "my email is na**@dm.com and @01 and noemail@test are
not emails but na***@md.net is again";

string b = Regex.Replace(a, @"(?<name>\w+([-+.]\w+)+)@(?<domain>
\w+([-.]\w+)*\.\w+([-.]\w+)*)", "${name}(at)${domain}");

string c = Regex.Replace(a, @"(?<=\w+([-+.]\w+)+)(at)(?>\w+([-.]
\w+)*\.\w+([-.]\w+)*)", "(at)");

Am I doing something wrong?

Thanks,
Miguel
Nov 20 '08 #5

P: n/a
Hello shapper,
On Nov 20, 11:12 am, Jesse Houwing <jesse.houw...@newsgroup.nospam>
wrote:
>Hello shapper,
>>On Nov 20, 2:33 am, Arne Vajhøj <a...@vajhoej.dkwrote:

shapper wrote:

I have a text as follows:
>
"My email is someth...@something.xyz and I posted this @ 2 am"
>
I need to replace the @ by (AT) bu only the ones that are in email
addresses.
>
All other @ shouldn't be replaced.
>
I know how to replace all @ but I am having problems in replacing
only the @'s in the email addresses.
>
How can I do this?
>
Regex.Replace with a reasonable regex expression for valid email
addresses should give a reasonable correct replacement.

Arne

Hi,

I was trying that but I have two problems:
return Regex.Replace(text,
"\w+([-+.]\w+)*@\w+([-.]\w+)*\.\w+([-.]\w+)
*", "(at)");
First I get a lot of errors on the pattern in each \ character:
Unrecognized escape sequence
The second problem is that this identifies all emails on my string
but I don't want to replace the emails but the @ in the emails.
There are two options here: Either capture the first and second part
of the email in a group and put them back in.

Second, match only the @, but use lookahead and lookbehind
constructions to make sure you only replace the @ in an emailaddress

So here we go:

capture the first and last parts and replace:

(?<name>\w+([-+.]\w+)+)@(?<domain>\w+([-.]\w+)*\.\w+([-.]\w+)*))

and replace that with:

${name}(at)${domain}

This should be quite easy to understand. Capture the parts you want
to keep in a named group (?<name>..) and put them back into the
replacement pattern ${name}.

The second option using look arounds:

(?<=\w+([-+.]\w+)+)(at)(?>\w+([-.]\w+)*\.\w+([-.]\w+)*))

and replace that with:

(at)

This one is usually harder to understand. (?<=...) looks back in your
string
and tries to find the pattern that is defined at the '...'. If it
cannot
find this exact pattern the whole expression fails.
(?>...) essentially does the same, but looks ahead, instead of
backwards.
The funny thing is, that even though you search for something in your
regex,
it doesn't become part of the actual Match and therefore doesn't get
replaced.
Now to touch on your issue with th escape sequences. Any special
character
sequence in regex starts with a \. And any escape sequence in C# code
starts
with a \ as well, so if you put a regex in a string you again have
two options:
First, escape all your \'s in your regex by putting an additional \
in front
of it. eg. \w becomes \\w. Second option is to use verbatim strings
in C#
by placing an @ in front of the string definition like this:
@"\w...more
regex goes here".
Hope this helps

--
Jesse Houwing
jesse.houwing at sogeti.nl
Hello,

I tried to use your code but in both expressions I get the error "to
many )'s".
I counted the ( and ) and removed the last ) in both expressions.
Now I don't get the error but the @ in the emails are not replaced.
This is what I have:

string a = "my email is na**@dm.com and @01 and noemail@test are
not emails but na***@md.net is again";

string b = Regex.Replace(a, @"(?<name>\w+([-+.]\w+)+)@(?<domain>
\w+([-.]\w+)*\.\w+([-.]\w+)*)", "${name}(at)${domain}");

string c = Regex.Replace(a, @"(?<=\w+([-+.]\w+)+)(at)(?>\w+([-.]
\w+)*\.\w+([-.]\w+)*)", "(at)");

Am I doing something wrong?

Loosk liek I made an error while copying part of your expression:
string b = Regex.Replace(a, @"(?<name>\w+([-+.]\w+)*)@(?<domain>
\w+([-.]\w+)*\.\w+([-.]\w+)*)", "${name}(at)${domain}");

string c = Regex.Replace(a, @"(?<=\w+([-+.]\w+)*)(at)(?>\w+([-.]
\w+)*\.\w+([-.]\w+)*)", "(at)");
Try these...
--
Jesse Houwing
jesse.houwing at sogeti.nl
Nov 21 '08 #6

This discussion thread is closed

Replies have been disabled for this discussion.