Thanks, that's exactly what I was looking for.
-Josh
On Thu, 01 Jul 2004 15:17:41 -0700, Lars Torben Wilson <[EMAIL PROTECTED]> wrote:
>
> Josh Close wrote:
>
> > I'm trying to get a simple regex to work. Here is the test script I have.
> >
> > #!/usr/bin/php -q
> > <?
> >
> > $string = "hello\nworld\n";
> > $string = preg_replace("/[^\r]\n/i","\r\n",$string);
>
> First, the short version. You can fix this by using backreferences:
>
> $string = preg_replace("/([^\r])\n/i", "\\1\r\n", $string);
>
> Now, the reason:
>
> preg_replace() replaces everything which matched, so both the \n and
> the character before it will be replaced (as they both had to match
> to make the pattern match).
>
> Luckily, preg_replace() stores a list of matches, which you can use
> either later in the same pattern or in the replace string. This is
> called a 'backreference'. You can tell preg_replace() which part(s) of
> the pattern you want to store in this fashion by enclosing those parts
> in parentheses.
>
> In your case, you want to store the character before the \n which matched,
> so you would enclose it in parentheses like so: "/([^\r])\n/i". Thereafter
> you can refer to that portion of the pattern match with the sequence \1.
> If you add another set of parens, you would refer to it with \2...and so
> on. You can even nest pattern matches like this, in which case they are
> counted by the opening paren. So the replacement string would then become
> "\\1\r\n". (You need the extra \ in front of \1 to prevent PHP's string
> interpolation parsing the \1 before it gets passed to preg_replace()).
>
> A lot more information is available from the manual page on preg_replace():
>
> http://www.php.net/preg_replace
>
> There is also an extensive pages on pattern syntax:
>
> http://www.php.net/manual/en/pcre.pattern.syntax.php
>
> Hope this helps,
>
> Torben
>
>
>
> > $string = addcslashes($string, "\r\n");
> >
> > print $string;
> >
> > ?>
> >
> > This outputs
> >
> > hell\r\nworl\r\n
> >
> > so it's removing the char before the \n also.
> >
> > I just want it to replace a lone \n with \r\n
> >
> > -Josh
>
>
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