template in unpack

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

hello monks,, can you tell what the use of using x2 template in unpack. i read in the documentation as, x A null byte. X Back up a byte. but i didnt understand crealy. i also tried with the example. can you please give me some code which explain that.

Comment on template in unpack

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Re: template in unpack by GrandFather (Saint) on Feb 10, 2006 at 09:33 UTC
`use warnings; use strict; my $str = '1234567890'; my @unpacked = unpack 'A1 x2 A1 X2 A1', $str; print "@unpacked";` [download] Prints: `1 4 3` [download] A1 gets the first character (1), x2 skips two (23), A1 gets one character (4), X2 backs up two characters (43), A1 gets one character (3). BTW `print "@unpacked";` prints the elements in @unpacked with spaces between them as `print join ' ', @unpacked;` would. DWIM is Perl's answer to Gödel	[reply] [d/l] [select]

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Re: template in unpack
by GrandFather (Saint) on Feb 10, 2006 at 09:33 UTC

use warnings;
use strict;

my $str = '1234567890';
my @unpacked = unpack 'A1 x2 A1 X2 A1', $str;

print "@unpacked";
[download]

Prints:

1 4 3
[download]

A1 gets the first character (1), x2 skips two (23), A1 gets one character (4), X2 backs up two characters (43), A1 gets one character (3).

BTW print "@unpacked"; prints the elements in @unpacked with spaces between them as print join ' ', @unpacked; would.

DWIM is Perl's answer to Gödel

[reply]
[d/l]
[select]