printing array using map

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

Replies are listed 'Best First'.
Re: printing array using map by oko1 (Deacon) on Apr 27, 2008 at 17:14 UTC
Is there a reason you insist on using 'map'? An explicit 'for' loop would be more legible. Not that I dislike 'map', but once past a certain degree of complexity, you really should break it out. `#!/usr/bin/perl -wl use strict; print for map { y/[]//d; join " ", reverse split } <DATA>; __DATA__ w1 w2 w3 [t4 w4] w5` [download] Update: My assumption is the opposite of netwallah's, since 'map' would print an arrayref as 'ARRAY(0xDEADBEEF)' rather than '[foo bar]'. -- Human history becomes more and more a race between education and catastrophe. -- HG Wells	[reply] [d/l]
Re^2: printing array using map by Anonymous Monk on Apr 27, 2008 at 18:26 UTC
Actually lets make this more clear, let's say I have an text file like this : `w1 w2 w3 [t4 w4] w5 w6` [download] and I want to process it to have something like this in output : `w1 w2 w3 w4 t4 w5 w6` [download] each w is a token and t is a lable for some tokens. I've tried this but it dosnt work and I get the same output. `use strict; my $file = $ARGV[0]; open IN, $file or die "Can't open"; my @file =<IN>; close IN; m/\[(\S+)\s(\S+)\]/ ? print qq[$2 $1\n] :print qq[$_] for @file;` [download] while my file is a text with my data as below. `w1 w2 w3 [t4 w4] w5 w6` [download]	[reply] [d/l] [select]
Re^3: printing array using map by johngg (Canon) on Apr 27, 2008 at 20:53 UTC
Firstly, using the readline operator with no filehandle defaults to opening and reading the files supplied as command-line arguments so you don't need to open the filehandle yourself. Secondly, you can use just one capture in the regex by using a negated character class, in other words capture zero or more non closing square brackets. `use strict; use warnings; print map { chomp; s{^\[([^\]]*)\]}{$1}; qq{$_\n}; } <>;` [download] Running it gives `J:\johngg\Scripts\Monks>type spw683152.dat w1 w2 w3 [t4 w4] w5 w6 J:\johngg\Scripts\Monks>perl spw683152 spw683152.dat w1 w2 w3 t4 w4 w5 w6` [download] I hope this is useful. Cheers, JohnGG	[reply] [d/l] [select]
Re^4: printing array using map by GrandFather (Saint) on Apr 27, 2008 at 21:54 UTC
Re^5: printing array using map by johngg (Canon) on Apr 27, 2008 at 22:01 UTC
Re^4: printing array using map by FunkyMonk (Bishop) on Apr 27, 2008 at 22:22 UTC
Re^5: printing array using map by johngg (Canon) on Apr 28, 2008 at 10:04 UTC
Re^3: printing array using map by FunkyMonk (Bishop) on Apr 27, 2008 at 22:19 UTC
In what way does oko1's solution not work for you? Using your input of: `w1 w2 w3 [t4 w4] w5` [download] produces: `w1 w2 w3 w4 t4 w5` [download] using an elegance I'd be proud of. Is that not what you're after? Unless I state otherwise, my code all runs with strict and warnings	[reply] [d/l] [select]
Re: printing array using map by NetWallah (Canon) on Apr 27, 2008 at 17:06 UTC
It is not clear whether "[t4 w4]" is an array reference, or plain text. Assuming the latter : `my @a=(qw(w1 w2 w3),"[t4 w4]" ,qw(w5 w6)); m/\[(\S+)\s(\S+)\]/ ? print qq[$2 $1\n] :print qq[$_\n] for @a` [download] FYI - it is pointless using "map" in a void context - "for" is preferable. If you have an array ref, the code is: `my @a=(qw(w1 w2 w3),["t4","w4"],qw(w5 w6)); ref $_ ? print "$_->[1] $_->[0]\n" :print qq[$_\n] for @a` [download] Of course, for production-level code, you would do a lot more error-checking. "How many times do I have to tell you again and again .. not to be repetitive?"	[reply] [d/l] [select]