From: "John W. Krahn" <[EMAIL PROTECTED]>
> Pavle Lukic wrote:
> > Problem
> > Given a string and a pattern, construct new string
> > by removing part of the string equal to pattern.
> > Remove only first occurrence of the pattern.
> >
> > Problem solutions
> >
> > Solution #1 ($x = $a) =~ s/\Q$b//;
> >
> > Solution #2 $x =
> > substr($a,0,index($a,$b)).substr($a,index($a,$b)+length($b));
>
> Too complicated. :-)
>
> substr $x = $a, index( $a, $b ), length( $b ), '';
>
> John
Too obfuscated. Very few people would have any chance understanding
what's going on in this statement.
This
$x = $a;
substr $x, index( $a, $b ), length( $b ), '';
should not be much slower (if at all) yet it's much easier to read.
perldoc -f substr
substr EXPR,OFFSET,LENGTH,REPLACEMENT
substr EXPR,OFFSET,LENGTH
substr EXPR,OFFSET
Extracts a substring out of EXPR and returns it. First
character
is at offset "0", or whatever you've set "$[" to (but
don't do
that). If OFFSET is negative (or more precisely, less
than
"$["), starts that far from the end of the string. If
LENGTH is
omitted, returns everything to the end of the string. If
LENGTH
is negative, leaves that many characters off the end of
the
string.
...
An alternative to using substr() as an lvalue is to
specify the
replacement string as the 4th argument. This allows you
to
replace parts of the EXPR and return what was there
before in
one operation, just as you can with splice().
P.S.: If you really wanted to keep this as a single command I'd
recommend adding some parens:
substr ($x = $a, index( $a, $b ), length( $b ), '');
or
substr (($x = $a), index( $a, $b ), length( $b ), '');
so that it's clear what's being assigned to the $x.
Plus I find
substr (($x = $a), index( $a, $b ), length( $b )) = '';
slightly easier to read.
Jenda
===== [EMAIL PROTECTED] === http://Jenda.Krynicky.cz =====
When it comes to wine, women and song, wizards are allowed
to get drunk and croon as much as they like.
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