Splitting a string in Perl

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

Hi Monks

I am trying to split a string into three parts. However, I am finding it difficult to come up with the appropriate pattern to help me split this string. Hence, could any monk kindly him me figure this out?

-MEMADDR-  ----HEX REPRESENTATION----       ---ASCII---  
0000       21 74 63 5f 37 5f 31 5f 36        !tc_7_1_6
[download]

my($memAddr, $data, $ascii);
open(DATAFILE $filename)
while(<DATAFILE>)
{
my $line = $_;
($memAddr, $data, $ascii) = split(/PATTERN/, $line);
[download]

I am trying to get a pattern the will result to me having the following values

 
$memAddr = 0000;
$data    = 2174635f375f315f36; # I think I need join() to get this for
+mat
$ascii   =  !tc_7_1_6
[download]

I will highly appreciate a help for any Monk out there.

Comment on Splitting a string in Perl Select or Download Code

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Re: Splitting a string in Perl by dragonchild (Archbishop) on Apr 25, 2008 at 20:39 UTC
That looks to be a fixed-width representation. That is better handled using unpack instead. `my ($memAddr, $data, $ascii) = unpack( "A10A20A", $line );` [download] I guessed at the 10 and 20, but those are the column widths. The means "and everything else". Then, you will want to massage in some fashion the various bits. So, something like `$data =~ s/\s//g;` to remove the whitespaces. Etc. My criteria for good software: Does it work? Can someone else come in, make a change, and be reasonably certain no bugs were introduced?	[reply] [d/l] [select]
Re: Splitting a string in Perl by gamache (Friar) on Apr 25, 2008 at 20:32 UTC
`my ($memAddr, $data, $ascii) = split /\s{2,}/, $line; # split line at + 2+ spaces $data =~ s/ //g; # remove whitespace from $data chomp $ascii; # remove EOL from $ascii` [download]	[reply] [d/l]
Re^2: Splitting a string in Perl by gzayzay (Sexton) on Apr 25, 2008 at 20:48 UTC
Thanks, your're my hero.. It works exactly as I wanted it	[reply]
Re: Splitting a string in Perl by holli (Abbot) on Apr 25, 2008 at 20:43 UTC
`print join ('', unpack 'A4x7A26x8A', '0000 21 74 63 5f 37 5f 3 +1 5f 36 !tc_7_1_6');` [download] holli, /regexed monk/	[reply] [d/l]
Re: Splitting a string in Perl by FunkyMonk (Bishop) on Apr 25, 2008 at 20:37 UTC
You're going to have a hard time using split to split this line (what if the hex is 20 20 20 - that'll give 3 spaces in ASCII, or what if the length of the data isn't a multiple of nine). You'll be better of using unpack. Unless I state otherwise, my code all runs with strict and warnings	[reply] [d/l] [select]
Re^2: Splitting a string in Perl by kyle (Abbot) on Apr 26, 2008 at 19:07 UTC
Good catch! To make a split solution work here, you'd need the optional third argument. `use Data::Dumper; my $in = '0000 21 20 20 20 20 20 20 20 36 ! 6'; my @out = split /\s{2,}/, $in, 3; print Dumper \@out; __END__ $VAR1 = [ '0000', '21 20 20 20 20 20 20 20 36', '! 6' ];` [download]	[reply] [d/l]
Re: Splitting a string in Perl by johngg (Canon) on Apr 25, 2008 at 21:08 UTC
I agree with other Monks that unpack is the way to go but if you are more comfortable with split I would use that in combination with splice and join in stages. Something like (not tested) `my @flds = split m{\s+}, $line; my $memAddr = splice @flds, 0, 1; my $ascii = splice @flds, -1, 1; my $data = join q{}, @flds;` [download] I hope this is useful. Cheers, JohnGG	[reply] [d/l]
Re: Splitting a string in Perl by ww (Archbishop) on Apr 25, 2008 at 20:55 UTC
Your `/PATTERN/` appears to be whitespace (`/s+`). Answers re `split` (and, as it happens, re `join`) can be found at `perldoc -f split`. Working code (to your specs, except for using `__DATA__` rather than a file as the data source): `#!/usr/bin/perl use strict; use warnings; my($memAddr, $data, $ascii, @lines, $line); # open(DATAFILE $filename) # while(<DATAFILE>) @lines = <DATA>; for $line(@lines) { chomp $line; ($memAddr, $data, $ascii) = split(/\s\s+/, $line); $data = join('', split(/\s/, $data)); print "$memAddr $data $ascii \n"; } __DATA__ -MEMADDR- ----HEX REPRESENTATION---- ---ASCII--- 0000 21 74 63 5f 37 5f 31 5f 36 !tc_7_1_6 1234 0f bb ac 11 a6 82 ff 5f 27 !xy_8_1` [download]	[reply] [d/l] [select]