Re^2: Is there a better way to generate unique set of random numbers ?

Thank you

I am still a beginner in perl, can you help me understand $seen{$candidate}++ in line:

redo if $seen{$candidate}++;
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Re^3: Is there a better way to generate unique set of random numbers ? by moritz (Cardinal) on Jul 28, 2011 at 10:02 UTC
`%seen` is a hash. If the key `$candidate` is not present in the hash, it is added to the hash (that's called "autovivification"), initialized to 1, and `undef` is returned - the redo is not executed. On the other hand if the key is already present in the hash, the corresponding value (for example 1) is returned, and incremented by one (for example set to 2). In this case the interesting part is not the incrementing, but that it returns a true value, so the `redo` is executed. Perl 6 - second systems done right	[reply] [d/l] [select]

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Re^3: Is there a better way to generate unique set of random numbers ?
by moritz (Cardinal) on Jul 28, 2011 at 10:02 UTC

%seen

$candidate

undef

redo

On the other hand if the key is already present in the hash, the corresponding value (for example 1) is returned, and incremented by one (for example set to 2). In this case the interesting part is not the incrementing, but that it returns a true value, so the redo is executed.

Perl 6 - second systems done right

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[d/l]
[select]