Re: hash key not found .. WHY NOT?
Paul Lalli
> I'm trying to merge two files by a common key field.
>
> filea.csv format:
> B1,B2,B3,B4,BK
>
> fileb.csv format:
> A1,AK,A3,A4
>
> Need to produce:
> filec.csv:
> A3,A4,B2,B3,B4,BK
>
> Where file1.csv is using BK=AK to lookup A3 and A4. Every record in
> filea.csv must end up in filec.csv
Not a word of this makes sense nor matches your sample data. There is
NO 'file1.csv' in your sample data, the phrase "BK=AK to lookup A3 and
A4" is meaningless, and NOT every element of filea.csv is found in
filec.csv. So what the heck are you talking about?
Please show REAL sample input and REAL sample output.
> Here's the code I have :
> #!/usr/bin/perl
You're using neither strict nor warnings. Why? For what reason do you
not want Perl to tell you when you're doing something wrong?
use strict;
use warnings;
> open FILEC, '>filec.csv' or die "could not open 'matched.csv' $!";
This error message does not match the code. If you can't open
filec.csv, you tell the user that you can't open matched.csv. Why?
> my %a;
> open FILEA, 'filea.csv' "could not open 'filea' $!";
> while ( <FILEA> ) {
> $_ =~ s/"([^"]*)"/&comma_fixer($1)/ge;
Have you accounted for the possibility that a field could contain an
escaped double quote?
> my @f = split /,/;
> my $key = $f[4];
> #print $key;
You're clearly having problems with $key, so why is this commented out?
What output do you get when it's not commented out?
> if ( exists $a{$key} )
> {
> print "Duplicate key found in ", $key ," ",$_," ", @f,"\n";
Have you never heard of interpolation?
print "Duplicate key found in $key $_ @f\n";
> }
> else
> {
> $a{$key} = \@f;
> }
> }
>
At this point, try using Data::Dumper to examine exactly what's inside
%a, and see if it matches your expectation.
use Data::Dumper;
print Dumper(\%a);
> open FILEB, 'fileb.csv' or die "could not open 'fileb' $!";
> while ( <FILEB> ) {
> my @b = split /,/;
> my $key = $b[1];
> #BELOW IS THE SUSPECT LINE
> if ( exists $a{$key} ) {
> my $m = join ',', $key,
> $a{$key}[2],
> $b[1],
> $b[2],
> $b[3];
> print FILEC "$m\n";
> print "entry found\n";
> }
> else
> {
> # print "key not found ",$key,"\n";
Why is this commented out? Don't you want to know what values of $key
were not found? Don't you want to compare them to the other part of
this code where you're adding keys to %a?
> }
>
> }
>
> close FILEA;
> close FILEB;
> close FILEC;
>
> sub comma_fixer {
> $string = @_[0];
> $string =~ s/,/ /g; ## replace , with blank,
> return $string;
>
>
> =====
>
> Every single line spits out "key not found".
No, it doesn't, since A) you commented out that line, and B) if you
hadn't you would have printed the key along with it. So what was the
ACTUAL output with those lines uncommented?
> What am I doing wrong
Not showing real data, not usefully using debugging statements.
> and is there a better way to approach this?
Yes. Use a module actually designed for processing CSV files. Go to
http://search.cpan.org and search for "Text::CSV"
Paul Lalli