Regex help with removing double quotes

[Schroeder, AJ]

Hello group,

I am attempting to remove double quotes from the beginning and ending of a
string. Admittedly, I am not the best with regular expressions, but I do
have two that work with preg_replace(). Here they are:

$pattern = '[^"]'; <--- removes the beginning double quote
$pattern = '["$]'; <--- removes the ending double quote

But when I try to make this all one statement with:

$pattern = '[^"].*["$]';

PHP throws a warning with an unknown modifier '.'. I then tried to enclose
'.*' in parentheses and I get an unknown modifier '('.

This is getting beyond my regex knowledge, if anyone has any advice on this
it would be greatly appreciated.

Thanks in advance,

AJ Schroeder

[Justin Koivisto]

when using preg_* you need escape chars for the expression....

your first patterns should look something like:

$pat = '`^"`'; // quote at beginning of string

$pat = '`"$`'; // quote at end of string

$pat = '`^"(.*)"$`'; // single-line string that starts and ends with a quote

--
Posted via a free Usenet account from http://www.teranews.com

[Schroeder, AJ]

Hmm, maybe I am that dense, but that last expression seemed to torch the
entire string and return nothing. The first two work no problem.

Still confused...

[Rik Wasmus]

On Mon, 05 Nov 2007 20:11:49 +0100, Schroeder, AJ <a...@qg.com> wrote:

> Hello group,
>
> I am attempting to remove double quotes from the beginning and ending of
> a
> string. Admittedly, I am not the best with regular expressions, but I do
> have two that work with preg_replace(). Here they are:
>
> $pattern = '[^"]'; <--- removes the beginning double quote
> $pattern = '["$]'; <--- removes the ending double quote
>
> But when I try to make this all one statement with:
>
> $pattern = '[^"].*["$]';
>
> PHP throws a warning with an unknown modifier '.'. I then tried to
> enclose
> '.*' in parentheses and I get an unknown modifier '('.

Yes indeed.
The preg_* function expect a pattern like this:
(delimiter)(pattern)(delimiter)(modifiers)

You are free to choose your own delimiter ('/' is pretty standard), and a
second occurance of that character is assumed to end the pattern and start
the modifiers. (I'm actually quite ammazed it matches '[' to ']', a quite
rigid implementation would throw an error stating that " was an unknown
modifier).

$string = preg_replace('/(^"+|"+$)/','',$string);
--
Rik Wasmus

[Justin Koivisto]

The last pattern assumes the string is a single line (no \r or \n in
it), and both begins and ends with "

This would match that pattern:
"The fox jumped over the lazy dog."

This would not:
The fox jumped over the "lazy" dog.

If you want to match as in the second string, try something more along
the lines of:

$pat = '`"([^"]*)"`';

When you are unsure how your patterns are matching, try something like
this to view it quickly:

if(preg_match_all($pat,$string,$m)){
echo '<pre>';
print_r($m);
echo '</pre>';
}

see the manual page for preg_match_all if you are not sure what the $m
array means.

[Justin Koivisto]

The last pattern assumes the string is a single line (no \r or \n in

it), and both begins and ends with "

This would match that pattern:
"The fox jumped over the lazy dog."

This would not:
The fox jumped over the "lazy" dog.

If you want to match as in the second string, try something more along
the lines of:

$pat = '`"([^"]*)"`';

When you are unsure how your patterns are matching, try something like
this to view it quickly:

if(preg_match_all($pat,$string,$m)){
echo '<pre>';
print_r($m);
echo '</pre>';
}

see the manual page for preg_match_all if you are not sure what the $m
array means.

--

[Schroeder, AJ]

Justin and Rik,

Thank you for the help! I am now able to strip off beginning and ending
quotes of strings. Although I am still messing around with different strings
to handle all the combination of strings I will have to process, I have a
great starting point.

Thank you again.

AJ Schroeder