help with an array

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

Replies are listed 'Best First'.
Re: help with an array by blazar (Canon) on Jul 29, 2005 at 15:26 UTC
`use strict;` [download] `use warnings; # as well!` [download] `my $countline = 0; my $mytest; open (MYFILE,"<testing.txt")\|\|die "Could not open input file\n";` [download] (A matter of personal preference but `open my $fh, '<', "testing.txt" or die "Could not open input file: $!\ +n";` [download] may be better. Pay attention to all the details...) `while($mytest = <MYFILE>) {` [download] You may want `while( defined($mytest = <MYFILE>) ) {` [download] to be more precise. Which is a good reason IMHO to use Perl's idiomatic `while(<MYFILE>) {` [download] `my @datas= split (/\s+/, $mytest); if ($datas[0] eq "Hello")` [download] Incidentally, no need to create the array: `if ( (split /\s+/, $mytest)[0] eq "Hello" )` [download] works just fine. Also, splitting on `/\s+/` is actually different from splitting on `' '` (see perldoc -f split) but the latter is in most cases what one really wants, and in fact it is also the default. So, had you also used the topicalizer as hinted above, this may have been just as simple as `if ( (split)[0] eq "Hello" )` [download] and in that case I would have used it as a statement modifier: `$countline++ if +(split)[0] eq "Hello";` [download] `my @test1 = $countline; print $test1[0];` [download] Huh?!? all in all if I understand correctly what that you want to achieve, this may have been just as simple as `while (<>) { push @wanted, $_ if +(split)[0] eq "Hello" }` [download] (but you may also want to chomp.)	[reply] [d/l] [select]
Re: help with an array by ikegami (Patriarch) on Jul 29, 2005 at 15:07 UTC
Use `push(@array, $mytest);` where you currently count: `use strict; use warnings; my $mytest; my @array; open(MYFILE, '<', 'testing.txt') \|\| die "Could not open input file\n"; while ($mytest = <MYFILE>) { my @datas = split(/\s+/, $mytest); push(@array, $mytest) if $datas[0] eq "Hello"; } # my $countline = @array; print("The matching lines:\n"); foreach my $line (@array) { print($line); }` [download] or `use strict; use warnings; open(MYFILE, '<', 'testing.txt') \|\| die "Could not open input file\n"; my @array = grep { my @datas = split(/\s+/, $_); $datas[0] eq "Hello" } <MYFILE>; # my $countline = @array; print("The matching lines:\n"); foreach my $line (@array) { print($line); }` [download]	[reply] [d/l] [select]
Re^2: help with an array by kwaping (Priest) on Jul 29, 2005 at 15:12 UTC
`push` was my first thought, but that would start the array off with element 0, not 1 as requested. The original post can have multiple interpretations though, so it's hard to say exactly what the desired result is without further clarification.	[reply] [d/l]
Re^3: help with an array by ikegami (Patriarch) on Jul 29, 2005 at 15:44 UTC
so add an extra push at the top.	[reply]
Re: help with an array by kwaping (Priest) on Jul 29, 2005 at 15:09 UTC
I might be misunderstanding the question, but if not, I think the solution is as easy as this: `use strict; my $countline = 0; my $mytest; my @array = (); #<- added line open (MYFILE,"<testing.txt")\|\|die "Could not open input file\n"; while($mytest = <MYFILE>) { my @datas= split (/\s+/, $mytest); if ($datas[0] eq "Hello") { $countline++; $array[$countline] = $countline; #<- added line } my @test1 = $countline; print $test1[0]; }` [download]	[reply] [d/l]
Re: help with an array by anonymized user 468275 (Curate) on Jul 29, 2005 at 15:24 UTC
Looks like a job for grep. `use strict; open (MYFILE,"<testing.txt")\|\|die "Could not open input file\n"; my @datas = grep /^Hello\s+/, <MYFILE>; my $countline = $#datas + 1; # or just treat $#datas as linecount-1` [download] One world, one people	[reply] [d/l]