using array elements for pattern matching in perl

Question

A newbie to Perl and regexes without saying, I am trying to use elements in an array in a perl regex. Here is the snippet

my $temp  = $line =~ s/somestring[^\n]*$_// for @myarray;

If I hard code the string instead of $_ it works fine. Also $_ prints the string fine in isolation. So what am I doing wrong? Even the expanded version of using a for loop doesn't yield a match.

P.S Just to clarify the array has just one element and I know it matches the line.

I'm not a Perl dev, but in REGEX $ has special meaning - it anchors to the end of the string, so it may need escaping. — Mitya
– Mitya, Commented Jul 13, 2012 at 17:33
@utkanos: Not necessary. Scalar variable interpolation works just fine inside of Perl regular expressions. perldoc perlop under the section "Quote and Quote Like Operators". — DavidO
– DavidO, Commented Jul 13, 2012 at 17:45
This is why I posted as a comment, not an answer. I was just saying that, in general REGEX grammar, the $ has special meaning. I'm not a Perl dev, so I didn't commit - I was just floating the idea. — Mitya
– Mitya, Commented Jul 13, 2012 at 17:50
A little more code might help, like actual values that illustrate the problem. I'm not sure what you're trying to accomplish or how it is failing. — RickF
– RickF, Commented Jul 13, 2012 at 18:10
Thank you @RickF. It did turn out to be a rather trivial oversight/misconception on my part and my question was answered. — ash
– ash, Commented Jul 13, 2012 at 18:21

Birei · Accepted Answer · 2012-07-13 17:40:54Z

4

It should work adding parentheses, although I hope that the content of the array hasn't special characters, because you will need to use quotemeta function to escape them.

my $temp;
($temp  = $line) =~ s/somestring[^\n]*$_// for @myarray;

answered Jul 13, 2012 at 17:40

Birei

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2 Comments

DavidO Over a year ago

The "special characters" issue is a good point. s/somestring[^\n]*\Q$_\E// is the more robust solution, unless the OP really wants the contents of $_ to be treated as a pattern.

ash Over a year ago

Thank you ! It helped. Robust solutions are always desirable. Helps me to start learning perl better.

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