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

Hi,

I'm viewing a code. Could somebody explain to me what does .= mean in the statement $hash{$k} .= "{$v}" where $k and $v are key and value of hash.

thanks,
riz

Retitled by davido from 'what does $hash{$k} .= "{$v}" class='add-text' size='.

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Re: what does $hash{$k} .= "{$v}"
by davido (Cardinal) on Feb 04, 2005 at 08:24 UTC

    It is an assignment and a concatenation all in one. Here are a few other variants:

    $string .= " world.";  # Concatenate and assign. Same as...
$string = $string . " world.";

$num += 5;    # Add and assign.  Same as...
$num = $num + 5;

$num -= 5;    # Subtract and assign. Same as...
$num = $num - 5;

$num *= 5;    # Multiply and assign.  Same as...
$num = $num * 5;

$num /= 5;    # Divide and assign.  Same as...
$num = $num / 5;

    [download]

    Dave

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Re: what does $hash{$k} .= "{$v}"
by Anonymous Monk on Feb 04, 2005 at 08:05 UTC
    It's an efficient way of writing: 
      $hash{$k} = $hash{$k} . "{$v}";

    [download]
    See man perlop.
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[d/l]

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