regexp help please

[Disco Octopus]

Hi,

I think I am need of a regular expression with regards to a str_replace
need that I have...

I have a string like this one...

"text text text{
text
} text {text text } t {text} txt { text }"

I need to replace all occurances of "{" with "{ " and "}" with " }" where
the following rules apply...

replace "{" with "{ " when the character to the right of "{" is NOT
<newline> and is NOT <space> and is NOT <tab>.

replace "}" with " }" when the character to the left of "}" is NOT
<newline> and is NOT <space> and is NOT <tab>.

So, the result in my example above would be....

"text text text{
text
} text { text text } t { text } txt { text }"

Would anyone possibly know how to do this?

Thanks

--
most midwives do not have children

[Justin Koivisto]

Re: regexp help please

Disco Octopus wrote:[color=blue]
> Hi,
>
> I think I am need of a regular expression with regards to a str_replace
> need that I have...
>
> I have a string like this one...
>
> "text text text{
> text
> } text {text text } t {text} txt { text }"
>
> I need to replace all occurances of "{" with "{ " and "}" with " }" where
> the following rules apply...
>
> replace "{" with "{ " when the character to the right of "{" is NOT
> <newline> and is NOT <space> and is NOT <tab>.
>
> replace "}" with " }" when the character to the left of "}" is NOT
> <newline> and is NOT <space> and is NOT <tab>.
>
> So, the result in my example above would be....
>
> "text text text{
> text
> } text { text text } t { text } txt { text }"
>
> Would anyone possibly know how to do this?[/color]

You would need to use both a zero-width negative look-ahead and a
zero-width negative look-behind with prel style regex...

<?php
$s =<<<EOS
text text text{
text
} text {text text } t {text} txt { text }
EOS;

$search1='`\{(? ![\s\r\n\t])`';
$replace1='{ ';
$s=preg_replace ($search1,$repl ace1,$s);

$search2='`(?<![\s\r\n\t])\}`';
$replace2=' }';
$s=preg_replace ($search2,$repl ace2,$s);

echo $s;

?>


--
Justin Koivisto, ZCE - justin@koivi.co m

http://koivi.com

[Chung Leong]

Re: regexp help please


Justin Koivisto wrote:[color=blue]
> Disco Octopus wrote:[color=green]
> > Hi,
> >
> > I think I am need of a regular expression with regards to a str_replace
> > need that I have...
> >
> > I have a string like this one...
> >
> > "text text text{
> > text
> > } text {text text } t {text} txt { text }"
> >
> > I need to replace all occurances of "{" with "{ " and "}" with " }" where
> > the following rules apply...
> >
> > replace "{" with "{ " when the character to the right of "{" is NOT
> > <newline> and is NOT <space> and is NOT <tab>.
> >
> > replace "}" with " }" when the character to the left of "}" is NOT
> > <newline> and is NOT <space> and is NOT <tab>.
> >
> > So, the result in my example above would be....
> >
> > "text text text{
> > text
> > } text { text text } t { text } txt { text }"
> >
> > Would anyone possibly know how to do this?[/color]
>
> You would need to use both a zero-width negative look-ahead and a
> zero-width negative look-behind with prel style regex...
>
> <?php
> $s =<<<EOS
> text text text{
> text
> } text {text text } t {text} txt { text }
> EOS;
>
> $search1='`\{(? ![\s\r\n\t])`';
> $replace1='{ ';
> $s=preg_replace ($search1,$repl ace1,$s);
>
> $search2='`(?<![\s\r\n\t])\}`';
> $replace2=' }';
> $s=preg_replace ($search2,$repl ace2,$s);
>
> echo $s;
>
> ?>
>
>
> --
> Justin Koivisto, ZCE - justin@koivi.co m
> http://koivi.com[/color]

\r, \n, \t are covered by \s already, so there is no need to specify
them separately. The code can be further compacted by using array
arguments to preg_replace():

$search = array('`\{(?!\s )`', '`(?<!\s)\}`');
$replace= array('{ ', ' }');
$s=preg_replace ($search,$repla ce,$s);

[Justin Koivisto]

Re: regexp help please

Chung Leong wrote:[color=blue]
> Justin Koivisto wrote:[color=green]
>> Disco Octopus wrote:[color=darkred]
>>> Hi,
>>>
>>> I think I am need of a regular expression with regards to a str_replace
>>> need that I have...
>>>
>>> I have a string like this one...
>>>
>>> "text text text{
>>> text
>>> } text {text text } t {text} txt { text }"
>>>
>>> I need to replace all occurances of "{" with "{ " and "}" with " }" where
>>> the following rules apply...
>>>
>>> replace "{" with "{ " when the character to the right of "{" is NOT
>>> <newline> and is NOT <space> and is NOT <tab>.
>>>
>>> replace "}" with " }" when the character to the left of "}" is NOT
>>> <newline> and is NOT <space> and is NOT <tab>.
>>>
>>> So, the result in my example above would be....
>>>
>>> "text text text{
>>> text
>>> } text { text text } t { text } txt { text }"
>>>
>>> Would anyone possibly know how to do this?[/color]
>> You would need to use both a zero-width negative look-ahead and a
>> zero-width negative look-behind with prel style regex...
>>
>> <?php
>> $s =<<<EOS
>> text text text{
>> text
>> } text {text text } t {text} txt { text }
>> EOS;
>>
>> $search1='`\{(? ![\s\r\n\t])`';
>> $replace1='{ ';
>> $s=preg_replace ($search1,$repl ace1,$s);
>>
>> $search2='`(?<![\s\r\n\t])\}`';
>> $replace2=' }';
>> $s=preg_replace ($search2,$repl ace2,$s);
>>
>> echo $s;
>> ?>
>>[/color]
> \r, \n, \t are covered by \s already, so there is no need to specify
> them separately.[/color]

That's what i thought, but I was too lazy to look it up. ;)
[color=blue]
> The code can be further compacted by using array
> arguments to preg_replace():
>
> $search = array('`\{(?!\s )`', '`(?<!\s)\}`');
> $replace= array('{ ', ' }');
> $s=preg_replace ($search,$repla ce,$s);[/color]

That is how I tested it, but then I pulled it apart for clarity of what
was going on.

--
Justin Koivisto, ZCE - justin@koivi.co m

http://koivi.com

[Disco Octopus]

Re: regexp help please

Chung Leong wrote:[color=blue]
> Justin Koivisto wrote:[color=green]
>> Disco Octopus wrote:[color=darkred]
>>> Hi,
>>>
>>> I think I am need of a regular expression with regards to a str_replace
>>> need that I have...
>>>[/color][/color][/color]

<....>
[color=blue][color=green]
>>
>> You would need to use both a zero-width negative look-ahead and a
>> zero-width negative look-behind with prel style regex...
>>
>> <?php[/color][/color]

<great stuff>
[color=blue][color=green]
>> ?>[/color][/color]
[color=blue]
>
> \r, \n, \t are covered by \s already, so there is no need to specify[/color]

<more great stuff>
[color=blue]
>
> $search = array('`\{(?!\s )`', '`(?<!\s)\}`');
> $replace= array('{ ', ' }');
> $s=preg_replace ($search,$repla ce,$s);[/color]

Thanks very much Juston and Chung. This works like a charm for me, and is
hugely appreciated.

--
if it itches, it will be scratched