1. For perl hashes, the only way to get matching keys of a hash for a given string, is performing a pattern match on the entire set of keys. 
my @matching_keys = grep /$customer/, keys %Customer;

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As some guy who used to be famous around here once said: "that's like buying and Uzi and using it to club your enemy to death".

It's also very misleading because the hash is serving no useful purpose in that construct.

It would be considerably cheaper to put the list of keys into an array and grep that than force Perl to re-walk the hash structure to generate the list of strings for grep each time around.

With the rise and rise of 'Social' network sites: 'Computers are making people easier to use everyday'
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.

In reply to Re^2: The Art of Hashing by BrowserUk
in thread The Art of Hashing by Anonymous Monk

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