Re^3: hashes with multiple values per key

Yes, "$yahoo{$key} += $value;" is the same as "$yahoo{$key} = $yahoo{$key} + $value;". Look under "Assignment operators" in perlop.

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Re^4: hashes with multiple values per key by GrandFather (Saint) on Aug 07, 2007 at 01:10 UTC
not quite. Consider: `use strict; use warnings; my $foo = undef; my $bar = undef; $foo += 1; $bar = $bar + 1;` [download] Generates the warning: `Use of uninitialized value in addition (+) at noname1.pl line 8.` [download] Note that it is the $bar line only that generates the warning. The update assignment operators do not generate an uninitialized value warning when the left hand side is undefined, but the other non-boolean binary operators do. See perlsyn Declarations. DWIM is Perl's answer to Gödel	[reply] [d/l] [select]

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Re^4: hashes with multiple values per key
by GrandFather (Saint) on Aug 07, 2007 at 01:10 UTC

not quite. Consider:

use strict;
use warnings;

my $foo = undef;
my $bar = undef;

$foo += 1;
$bar = $bar + 1;
[download]

Generates the warning:

Use of uninitialized value in addition (+) at noname1.pl line 8.
[download]

Note that it is the $bar line only that generates the warning. The update assignment operators do not generate an uninitialized value warning when the left hand side is undefined, but the other non-boolean binary operators do. See perlsyn Declarations.

DWIM is Perl's answer to Gödel

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