Re^3: printing array reference and storing this data in a hash.

The brackets are an anonymous array constructor. See perlref.

$var = [ split /:/, $_ ];
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means "make an anonymous array (an array reference) and insert into it the results of the split operation; then assign the reference to the variable $var".

More about split:

$_     = "Fracassus Cacus Eryx Anteus"; # see Acme::MetaSyntactic
$foo   = split;                         # '4'
$foo   = split /\s+/, $_;               # '4'
($foo)       = split /\s+/, $_;         # ('Fracassus')
($foo, $bar) = split /\s+/, $_;         # ('Fracassus', 'Cacus')
($foo, $bar) = split /\s+/, $_, 2;      # ('Fracassus', 'Cacus Eryx An
+teus')
($foo, $bar) = split /\s+/, $_, 1;      # ('Fracassus Cacus Eryx Anteu
+s', '')
($foo)       = split /\s+/, $_, 1;      # ('Fracassus')
($foo)       = (split /\s+/, $_,) [2];  # ('Eryx')
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It's odd that a split with LIMIT 1 behaves different when assigning to a list with a single or two variables; but it does. That's why I prefer to say

$foo = (split /\s+/, $_) [0];
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if I want just the first element of the resulting list. The (split)[0] thingy means "give me the element 0 of the list returned by split".

Thanks to BooK++ for Acme::MetaSyntactic

--shmem

update: added missing backslashes to /s+/ :~}

_($_=" "x(1<<5)."?\n".q·/)Oo.  G°\        /
                              /\_¯/(q    /
----------------------------  \__(m.====·.(_("always off the crowd"))."·
");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}

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Re^4: printing array reference and storing this data in a hash. by mikejones (Scribe) on Dec 19, 2006 at 20:13 UTC
cool thanks for the detail, but now I have played a little with certain fields of a /etc/passwd file and I am back to the original problem...its printing the hash address not the actual values. All I need is to store the name,uid,gid and comments into a hash from the @{$dublin_aref} which is the glob of passwd files opened via <FILE>. thank you use strict; use warnings; use diagnostics; my @dublinaray = glob("/home/user/passwd."); my $dublin_aref = \@dublinaray; my %dublin_hosts = (); my (@tmp_values,@dub_values,) = (); my ($dub_key,$name,$uid,$gid,$cmts,$dub_values); parse_file(); sub parse_file { foreach my $element ( @{$dublin_aref} ) { { local FILE; open (FILE, "+<$element") or die "dublin file '$element' did not o +pen: $!"; local $/ = undef; ($dub_key) = $element =~ m\|\.(\w+\.\w+)\z\|i; ($name) = (split /:/, <FILE>) [0]; ($uid) = (split /:/, <FILE>) [2]; ($gid) = (split /:/, <FILE>) [3]; ($cmts) = (split /:/, <FILE>) [4]; @tmp_values = ($name,$uid,$gid,$cmts); $dub_values = \@tmp_values; push ( @{$dublin_hosts{$dub_key}}, $dub_values ); } } while ( ($dub_key,$dub_values) = each %dublin_hosts ) { print Dumper("$dub_key => @{$dub_values}\n"); } [download] The code below works, yet I am still trying to figure out why the above code does not: `open (FILE, "+</cygdrive/c/temp/passwd.oftappp1.hpux"); my (@values,$name,$uid,$gid,$comments) = (); foreach my $file (<FILE>) { ($name) = (split /:/ , $file) [0]; ($uid) = (split /:/ , $file) [2]; ($gid) = (split /:/ , $file) [3]; ($comments) = (split /:/ , $file) [4]; @values = ($name,$uid,$gid,$comments); print join ("\t", @values,"\n"); }` [download]	[reply] [d/l] [select]
Re^4: printing array reference and storing this data in a hash. by mikejones (Scribe) on Dec 20, 2006 at 18:04 UTC
was wondering if you saw my most recent response? thx!	[reply]
Re^5: printing array reference and storing this data in a hash. by shmem (Chancellor) on Dec 20, 2006 at 18:26 UTC
For that type of questions, there's the messaging facility. Well, I was busy doing work (hrm. ;-) and reading other interesting posts. I also thought you would figure out, or somebody else would answer. `($name) = (split /:/, <FILE>) [0]; ($uid) = (split /:/, <FILE>) [2]; ($gid) = (split /:/, <FILE>) [3]; ($cmts) = (split /:/, <FILE>) [4];` [download] With that code, each split works on a new line read off the file handle FILE. The correct way would be: `($name, $uid, $gid, $cmts) = (split /:/, <FILE>)[0,2,3,4];` [download] --shmem _($_=" "x(1<<5)."?\n".q·/)Oo. G°\ / /\_¯/(q / ---------------------------- \__(m.====·.(_("always off the crowd"))."· ");sub _{s./.($e="'Itrs `mnsgdq Gdbj O`qkdq")=~y/"-y/#-z/;$e.e && print}	[reply] [d/l] [select]