map hash instead of map array

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

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Re: map hash instead of map array by shotgunefx (Parson) on Apr 04, 2002 at 12:12 UTC
`map { $hash{$_} = 'whatever' } keys %hash;` If you don't use keys on the hash, it will use hash like a list.. Giving key then value, key then value... -Lee "To be civilized is to deny one's nature."	[reply] [d/l]
Re: Re: map hash instead of map array by hakkr (Chaplain) on Apr 04, 2002 at 12:16 UTC
thanks was suffering mental blockage	[reply]
Re: map hash instead of map array by strat (Canon) on Apr 04, 2002 at 12:59 UTC
If you just want to change the values of the hash to a new hash, you could do something like: `my %newHash = (); @newHash{ keys %oldHash } = map { &quote($_) } values %oldHash;` [download] For keys and values always has to give an identical order. TIMTOWTDI :-) Best regards, perl -le "s==F=e=>y~\martinF~stronat~=>s~[^\w]~~g=>chop,print"	[reply] [d/l]
Re: map hash instead of map array by Juerd (Abbot) on Apr 04, 2002 at 12:18 UTC
do I have to translate me hash to an array or use 'keys' and 'values' Use keys or values, yes. You had the idea yourself, but apparently didn't try it. Often, you get results very fast and accurately by asking `perl` instead of asking Perl Monks. Update Here's the solution: `$_ = $sql->quote($_) for values %hash` [download] Don't use map where normal loops are good enough. U28geW91IGNhbiBhbGwgcm90MTMgY W5kIHBhY2soKS4gQnV0IGRvIHlvdS ByZWNvZ25pc2UgQmFzZTY0IHdoZW4 geW91IHNlZSBpdD8gIC0tIEp1ZXJk	[reply] [d/l]
Re: map hash instead of map array by Biker (Priest) on Apr 04, 2002 at 13:56 UTC
"I have decided I love map and want to use it for everything." `map()` builds and returns a list. (Or, in scalar context, the number of elements in the list constructed.) Don't use `map()` unless you intend to make use of the list returned. (Or the scalar containing the number of elements.) Update: As Juerd points out, `map()` returns a list or the number of scalars in the list. Not an array as I initially stated. Everything went worng, just as foreseen.	[reply] [d/l] [select]
Re: Re: map hash instead of map array by Juerd (Abbot) on Apr 04, 2002 at 14:03 UTC
map() builds and returns an array. (Or, in scalar context, the number of elements in the array constructed.) s/array/list/g Don't use map() unless you intend to make use of the array returned. s/array/list/ U28geW91IGNhbiBhbGwgcm90MTMgY W5kIHBhY2soKS4gQnV0IGRvIHlvdS ByZWNvZ25pc2UgQmFzZTY0IHdoZW4 geW91IHNlZSBpdD8gIC0tIEp1ZXJk	[reply]