Ajey Kulkarni <[EMAIL PROTECTED]> wrote:
: Subject: hi..
<sarcasm>
Great subject. So much better than "Need help with regex"
or "Need to escape []". Always keep us guessing.
</sarcasm>
: i want to 'insert' an escape character for every '[' & ']'
: i will find in a variable..
:
: Suppose $temp has a word which might contain [ and/or ].
: Eg: if $temp has hello]
: the modified temp should have hello\]
:
: if $value has [hello] i want the result to be \[hello\].
:
: Is there a quick one line regex to do this?
: i'm able to match the presence of [ & ]
: if( (/\[/)|(/\]/) ){
: my $value = $_;
: $value =~ s/\[/\\\[/;
: $value =~ s/\]/\\\]/;
: print $value;
: }
A one-liner is not necessarily better. You might want
to test. The substitution operator has a pattern on the
left side and a replacement string on the other. According
to 'perlop' it takes this form:
s/PATTERN/REPLACEMENT/egimosx
Let's take a look at your phrase:
s/\[/\\\[/
The PATTERN is '\[' and the REPLACEMENT is "\\\[". I
put the REPLACEMENT in double quotes because that is how
it is most commonly interpolated. To print '\[' we need
"\\[" on the REPLACEMENT side.
The PATTERN side views '[', and ']' as special
characters. So we need to escape them or we need to use
some other means to describe them. To look for more than
one we can place them in a character class: [\[\]] or as
[\][] then capture the one we match: ([\][]).
s/([\][])/\\$1/
We could also avoid the character class and use:
s/(\]|\[)/\\$1/
To capture multiple instances in the line we add 'g'.
s/([\][])/\\$1/g
And to make it easier to read we add x:
$value =~
s/ # start substitution
( # capture match in $1
[\][] # character class for [ and ]
) # end capture
/\\$1/gx; # replace with \[ or \] globally
Having said all this. I would still prefer Rob's
solution with two separate regexes in a 'foreach'.
HTH,
Charles K. Clarkson
--
Head Bottle Washer,
Clarkson Energy Homes, Inc.
Mobile Home Specialists
254 968-8328
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