Re: Hash value

Only the keys of a hash must be unique. Its values may repeat.

Printing the reverse of a hash does not reverse keys and values in the hash. For that to happen you must re-assign the reversed data back to the hash:

%hash = reverse %hash;
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The order in which a hash "prints" (or the order of the result of the keys, values or each function) is not random but determined by the internal hashing algorithm. For security reasons the order is likely to change between executions of your script although it is guaranteed to be the same order within one run of your script on the same (unmodified) hash.

So you cannot easily predict the order. If you need the keys (or values) ordered, the best way is to use sort.

CountZero

A program should be light and agile, its subroutines connected like a string of pearls. The spirit and intent of the program should be retained throughout. There should be neither too little or too much, neither needless loops nor useless variables, neither lack of structure nor overwhelming rigidity." - The Tao of Programming, 4.1 - Geoffrey James

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Re^2: Hash value by Bloodnok (Vicar) on Feb 10, 2009 at 11:21 UTC
... or, if you _do_ need predictable ordering (as the order the key-value pairs were entered), use Tie::IxHash A user level that continues to overstate my experience :-))	[reply]