Re: printing array using map

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]'.


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Comment on Re: printing array using map Download Code

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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
Why chomp when you put the newline back anyway? If the OP doesn't need to explicitly check for balanced brackets then the regex simplifies too: `print map {s/\[\|\]//g; $_} <>;` [download] Or if your taste runs to for loops and you don't mind the occasional comma operator: `s/\[\|\]//g, print for <>;` [download] Perl is environmentally friendly - it saves trees	[reply] [d/l] [select]
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
My understanding is that the OP wants the "[t4 w4]" input reversed on output: "w4 t4" Update: Gah. Corrected brackets. Thanks kyle Unless I state otherwise, my code all runs with strict and warnings	[reply]
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]