perl grep

[pmcmicha]

I am trying to do the following with no success and I cannot seem to find any good documentation on this problem.


open(LIST,"<test.txt");
@list = <LIST>;
close(LIST);

foreach $value (@unq) {\
chomp($value);
@ent = grep /^$value\|/, @list;
}


When I try this, the variable $value doesn't seem to work in the grep statement. The @ent array ends up with 0 entries even though it should have at least one inside of it. If I exchange $value for an unique entry like 831, then this works. I am unsure of this is not working.

Thanks.

 

[KevinADC]

it could be because you are redefining the @ent array each time you loop through @unq. Try this and see what you get:

open(LIST,"<test.txt");
@list = <LIST>;
close(LIST);

my @ent = ();
for my $i (0 .. $#unq) {\
    chomp($unq[$i]);
    $ent[$i] = grep /^$unq[$i]\|/, @list;
}

now @ent should hopefully contain a list of returned values from the grep function for each element of @unq. But this might work better stored in a hash (%ent) anyway:

open(LIST,"<test.txt");
@list = <LIST>;
close(LIST);

my %ent = ();
for my $i (0 .. $#unq) {\
    chomp($unq[$i]);
    $ent{$i} = grep /^$unq[$i]\|/, @list;
}

foreach my $keys (sort {$a <=> $b} keys %ent) {
   print "Index# $_ of \@unq returned: $ent{$keys}\n";
}

or something similar to that

 

[mikevh]

Or

foreach $value (@unq) {\
    chomp($value);
    [b]push(@ent, grep /^$value\|/, @list);[/b]
}