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in reply to split and uninitialized variables

You can do 
 
my ($x, $y, $z) = ('', '', '');
($x, $y, $z) = split(',', $_);

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OR 
my ($x, $y, $z) = map { $_ || '' } split(',', $_);

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to ensure the variables are initialised.

Update: Oops! I really need a new brain. 

use strict;
use warnings;

$_ = "a,0,b";
my ($x, $y, $z) = split(',', $_);
foreach ($x, $y, $z) { $_ = '' unless defined($_) }

print "x = $x\ny = $y\nz = $z\n";

__END__

x = a
y = 0
z = b

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Re^2: split and uninitialized variables
by ikegami (Patriarch) on Sep 03, 2004 at 15:31 UTC

    Your first solution

    my ($x, $y, $z) = ('', '', '');
($x, $y, $z) = split(',', $_);

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    won't work. Any values assigned in the first line will get overwritten in the second line:

    $_ = 'a,b';
my ($x, $y, $z) = ('', '', '');
($x, $y, $z) = split(',', $_);
print(defined($z)?'defined':'undefined', "\n");
# prints undefined.

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    Your second solution

    my ($x, $y, $z) = map { $_ || '' } split(',', $_);

    erases any '0'. Try:

    my ($x, $y, $z) = map { defined($_)?$_:'' } (split(',', $_))[0..2];

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    Personally, I'd go with the simple my ($x, $y, $z) = (split(',', $_), ('') x 3); solution mentioned elsewhere.

    Update: Added missing [0..2] as pointed out by Roy Johnson. Thanks.

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      Actually, the map solution doesn't work, because split doesn't return three elements, so you'd need to make it 
      my ($x, $y, $z) = map { defined($_) ? $_ : '' } (split(/,/, $_))[0..2]
+;

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      Caution: Contents may have been coded under pressure.
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Re^2: split and uninitialized variables
by Fletch (Bishop) on Sep 03, 2004 at 15:33 UTC

    Your first one's not going to work. 

    main::(-e:1):   0
  DB<1> $_ = "a,b"

  DB<2> x ($x,$y,$z) = ('default') x 3
0  'default'
1  'default'
2  'default'
  DB<3> x ($x,$y,$z) = split( ',', $_ )
0  'a'
1  'b'
2  undef

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Re^2: split and uninitialized variables
by antirice (Priest) on Sep 03, 2004 at 15:33 UTC

    Both methods have problems:

    > perl -wl
my ($x,$y,$z) = ('','','');
($x,$y,$z) = split(',','a,b');
print "$x $y $z";
__END__
Use of uninitialized value in concatenation (.) or string at - line 3.
a b

> perl -wl
my ($x, $y, $z) = map { $_ || '' } split(',', 'a,0,b');
print "$x $y $z";
__END__
a  b

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    The second one is easily fixed with:

    perl -wl
my ($x, $y, $z) = map defined $_ ? $_ : '', (split(',', 'a,0,b'))[0..2
+];
print "$x $y $z";
__END__
a 0 b

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    Update: Doh! Thanks !1 (silly lurker).

    antirice    
    The first rule of Perl club is - use Perl
    The     ith rule of Perl club is - follow rule i - 1 for i > 1

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