Using Text::CSV to find text with round brackets - not working - perl

Question

I have a csv file that I am searching for lines that contain a certain model. The program works perfectly when searching for '2GM' model but NOT for '2GM(F)'
This is the program:
#!/usr/bin/perl
# Searches modeltest.txt for all instances of model
# Writes a file called <your model>.txt with all lines
# in modeltest.txt where the model is found
# Edit $model for different uses
use strict;
use warnings;
use Text::CSV;
my $input_file = 'modeltest.txt';
my #lines = ();
# my $model = '2GM'; # Search for 2GM - WORKS PERFECTLY
my $model = '2GM(F)'; # Search for 2GM(F) - DOES NOT WORK!
# my $model = '2GM\(F\)'; # Does not work either!
print "Search pattern is $model\n";
my $output_file = $model . '.txt';
my $csv = Text::CSV->new({binary => 1, auto_diag => 1, eol=> "\012"})
or die "Cannot use CSV: ".Text::CSV->error_diag ();
print "Searching modeltest.txt for $model....\n";
open my $infh, '<', $input_file or die "Can't open '$input_file':$!" ;
open my $outfh, '>', $output_file or die "Can't open '$output_file':$!" ;
while (my $row = $csv->getline($infh))
{
my #fields = $csv->fields();
if (/^($model)$/ ~~ #fields) # search for pattern
{
$csv->print ($outfh, ["Y $fields[1]",$model]) or $csv->error_diag;
}
}
close $infh;
close $outfh;
$csv->eof or die "Processing of '$input_file' terminated prematurely\n";
print "All Done see output files...\n";
Here is the modeltest.txt file:
3,721575-42702,121575-42000,"PUMP ASSY, WATER",,26,COOLING SEA WATER PUMP,-,2GM(F),3GM(F),-,3HM,3HMF,,
1,721575-42702,121575-42000,"PUMP ASSY, WATER",,73,COOLING SEA WATER PUMP,-,2GM,3GM,-,3HM,-,,
45,103854-59191,,"BOLT ASSY, JOINT M12",W,38,FUEL PIPE,1GM,2GM(F),3GM(F),3GMD,3HM,3HMF,,
21,104200-11180,,"RETAINER, SPRING",,11,CYLINDER HEAD,1GM,2GM(F),3GM(F),3GMD,-,-,,
24,23414-080000,,"GASKET, 8X1.0",,77,FUEL PIPE,-,2GM,3GM,-,3HM,-,,
3,124223-42092,124223-42091,IMPELLER,,73,COOLING SEA WATER PUMP,-,2GM,3GM,-,3HM,-,,
Here is the output for 2GM.txt
"Y 721575-42702",2GM
"Y 23414-080000",2GM
"Y 124223-42092",2GM
There is no output for 2GM(F) - the program does not work! and I have no idea why?
Can anyone throw some light onto my problem?
YES this Worked Thank you again !!
Happy not to be using smartmatch...
Did the following:
Changed the search expression to
my $model = "2GM\(F\)";
Used the following code
while (my $row = $csv->getline($infh))
{
my #fields = $csv->fields();
foreach my $field (#fields)
{
if ($model eq $field) # search for pattern match in any field
{
$csv->print ($outfh, ["Y $fields[1]",$model]) or $csv->error_diag;
}
}
}

Answer 1

Parentheses have a special meaning in regular expressions, they create capture groups.
If you want to match literal parentheses(or any other special character) in a regular expression you need to escape them with backslashes, so your search pattern needs to be 2GM\(F\).
You can also use \Q and \E to disable special characters in your pattern match and leave your search pattern the same:
if (/^(\Q$model\E)$/ ~~ #fields) # search for pattern
...
The smartmatch operator ~~ is deprecated I believe, it would be more straightforward to loop over #fields:
foreach my $field ( $csv->fields() ) {
if (/^($model)/ =~ $field) # search for pattern
...
}
And really there is no reason to pattern match when you can compare directly:
foreach my $field ( #{$csv->fields()} ) {
if ($model eq $field) # search for pattern
...
}

Answer 2

It is best to use \Q in the regex so that you don't have to mess with escaping characters when you define $model.
The data is already in the array referred to by $row - there is no need to call fields to fetch it again.
It is much clearer, and may be slightly faster, to use any from List::Util
It's tidier to use autodie if all you want to do is die on an IO error
Setting auto_diag to a value greater than one will cause it to die in the case of any errors instead of just warning
This is a version of your own program with these issues altered
use strict;
use warnings;
use autodie;
use Text::CSV;
use List::Util 'any';
my $input_file = 'modeltest.txt';
my $model = '2GM(F)';
my $output_file = "$model.txt";
my $csv = Text::CSV->new({ binary => 1, eol => $/, auto_diag => 2 })
or die "Cannot use CSV: " . Text::CSV->error_diag;
open my $infh, '<', $input_file;
open my $outfh, '>', $output_file;
print qq{Searching "$input_file" for "$model"\n};
while (my $row = $csv->getline($infh)) {
if (any { /\Q$model/ } #$row) {
$csv->print($outfh, ["Y $row->[1]",$model]);
}
}
close $outfh;