term in last line of flatfile

alexiskb has asked for the wisdom of the Perl Monks concerning the following question:

How can i skip the last line in a flatfile, which is like so:

"ZYZYGY3",16-AUG-2002"
done,3485
[download]

where 'done' is the first thing on the line...
I have tried the following and it reads the line unless i add an extra return..i have added (\n) to show formatting marks


while (<PAST>) {
    next until $. > 1;
    $contents[$co] = $_;
    next if $_ =  /^done/;
    next if m/^\s+$/;
    $co++;
    }
[download]

"ZYZYGY1",16-AUG-2002"(\n)
"ZYZYGY2",16-AUG-2002"(\n)
"ZYZYGY3",16-AUG-2002"(\n)
done,3485(\n)
[download]

but works and removes the last lines in this example when i add an extra return after 'done'...

"ZYZYGY1",16-AUG-2002"(\n)
"ZYZYGY2",16-AUG-2002"(\n)
"ZYZYGY3",16-AUG-2002"(\n)
done,3485(\n)
(\n)
[download]

the error gives me "Use of uninitialized value in string...." if i do not get rid of this last line in a foreach loop... tks monks!

Comment on term in last line of flatfile Select or Download Code

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Re: term in last line of flatfile by demerphq (Chancellor) on Oct 10, 2002 at 16:55 UTC
I presume you want to skip the first line right? Thats what the `next until $. >1;` [download] is supposed to do? Except it doesnt. :-) until != unless. Also it isnt the best way to remove the first line, as it puts a conditional inside a loop that need not be. Then you have a problem with `next if $_ = /^done/;` [download] which is exactly equivelent to `next if $_= $_=~/^done/;` [download] Which isnt what you want at all. In addition I question whether that should really be last and not next. So I would say it should be `last if /^done/; #or #last if $_=~/^done/;` [download] But by the time I get to this point I reckon that you are trying to put all but the first and the (ostensibly) last record in the file into an array, skipping blank lines. If so I would write it as `my @contents; my $header=<PAST>; # extract the first line while (<PAST>) { next unless /\S/; # ignore whitespace only lines. last if /^done/; # finish when we hit a line starting with 'done +' #chomp; # uncomment if you dont want newlines in conten +ts. push @contents,$_; # add the line to the buffer }` [download] UPDATE: Assuming that the done line also contains a count then you may want to check that it matches with `my @contents; my $header=<PAST>; # extract the first line while (<PAST>) { next unless /\S/; # ignore whitespace only lines. if (/^done,(\d+)$/) { die "Count mismatch in trailer. Got $1 expected @{[scalar @con +tents]}" unless $1 == scalar(@contents); last; } #chomp; # uncomment if you dont want newlines in conten +ts. push @contents,$_; # add the line to the buffer }` [download] HTH --- demerphq my friends call me, usually because I'm late....	[reply] [d/l] [select]
Re: Re: term in last line of flatfile by alexiskb (Acolyte) on Oct 11, 2002 at 08:41 UTC
Great! that handles it perfectly, no errors at all.. thank you very much indeed... you are most kind, you were quite right i did have a header also! cheers!	[reply]
Re: term in last line of flatfile by kabel (Chaplain) on Oct 10, 2002 at 16:42 UTC
the "matching" operator is =~, not = and matching against $_ can save you a few chars: `next if (/^done/);` [download]	[reply] [d/l]
Re: term in last line of flatfile by admiraln (Acolyte) on Oct 10, 2002 at 16:45 UTC
You could reverse your test and match only what you are looking for : a quoted string , a comma, and a date. this would exclude all lines that don't match anywhere not just at the end. This is a "Good Idea" because the list of thing you don't what could be infinite and the things you do want should be very short.	[reply]
Re: term in last line of flatfile by blakem (Monsignor) on Oct 10, 2002 at 22:57 UTC
How can i skip the last line in a flatfile You could use `eof()` like this: `while(<PAST>) { last if eof(PAST); ... }` [download] -Blake	[reply] [d/l] [select]