perl: file open / line modify... kept me up late..

[Bill McNAMARA_1]

not sure this is _the_ perl forum, but I'll ask in any case..

I've the followin excerpt of a perl script, that is meant to read and modify data a file.

but it doesn't work of course..

#
# FILE originally contains following line
# one|two|three|0|1
# $q is one
#
open(FILE, ">$questionfile");
@correct = grep(/^\Q$q|\E/, );
close(FILE);
#
# FILE ends up blank
# should end up
# one|two|three|1|1
#
$q_line = $correct[0];
($aaa,$bbb,$ccc,$ddd,$eee) = split(/\|/, $q_line);
$fff =$ddd + 1;
$newline = "$aaa|$bbb|$ccc|$fff|$eee\n";
open(TMP, ">$tmp");
print TMP "$newline\n";
# ends up |||1|
close(TMP);


more or less, if there's a file that looks like this:

one|two|three|0|1
une|deux|trois|0|4
aon|do|tri|0|5

I want it to end up looking like this:
one|two|three|0|1
une|deux|trois|1|4
aon|do|tri|0|5

if the variable to search for, one, une, aon
is known and $q above..

Later,
Bill

[harry d brown jr]

Bill,

Your first file, $question file, is open for output ">$question". You need the open the file for input "<$question".

live free or die
harry

[Rodney Hills]

You may want to put a "chomp @correct" after the line

@correct=grep...

Input lines from files have the \n on them, sometimes they can be ignored, but usually you don't want them.

-- Rod Hills

[harry d brown jr]

Bill,
your problem is your grep statement. What are you looking for, because your grep is returning null??

live free or die
harry

[harry d brown jr]

Bill,

what are you trying to match on here:

@correct = grep(/^\Q$q|\E/, );

What is the "\Q" and "\E" for??

live free or die
harry

[Leslie Chaim]

Bill,

Just two points:
1. It appears to me that you need an exact match to the first column. Therefore, it is not a candidate for regex usage.
Use the eq operator instead:

@correct = grep $q eq $_, ;

You can include or omit the parens, Perl doesn't care:)

2. If all you need done is stated in your question, why not make use of Perl powerful command line interface:

perl -nalF'\|' -e "if (\$F[0] eq '$q') {\$F[3] +=1; print join '|', @F}" origfile > newfile

Assuming you have a shell variable $q set to somevalue.

Leslie