Merging two @ARRAYS into a %HASH

Hashes are a wonderful thing. They can be used to access structures in a clean and neat way.

Imagine you have a function that returns an @ARRAY of values, like localtime or stat. Wouldn't it be nice to be able to access the elements returned by their name? Here's how I do it:

my @datekeys = ("seconds","minutes","hour","mday","month","year","wday
+","yday","isdst");
my %localtime;
@localtime{@datekeys} = localtime( time );

printf "It now is %s:%s and the %d day of the week\n"
    ,$localtime{"hour"}
    ,$localtime{"minutes"}
    ,$localtime{"wday"}
;
[download]

Comment on Merging two @ARRAYS into a %HASH Download Code

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RE: Merging two @ARRAYS into a %HASH by howard40 (Beadle) on Feb 27, 2000 at 08:08 UTC
i like this example.... Reminds me of Turbo Pascal... the "fake" hashes that could be constructed using only arrays... heh...	[reply]
RE: Merging two @ARRAYS into a %HASH by btrott (Parson) on Feb 25, 2000 at 23:59 UTC
This is nice in a general purpose sense. In the specific instances you mention, though, you might want to also check out Time::localtime (and Time::gmtime) and File::stat, which provide by-name interfaces to their respective built-ins.	[reply]
RE: Merging two @ARRAYS into a %HASH by BBQ (Curate) on Apr 22, 2000 at 09:08 UTC
I didn't get it! :o( I always knew you could do $this, @this and %this (and even *this) within the same program... But what's this new @this{}? #!/home/bbq/bin/perl # Trust no1!	[reply]
RE: RE: Merging two @ARRAYS into a %HASH by chromatic (Archbishop) on Apr 22, 2000 at 09:30 UTC
It's a hash slice! Hash slices are wonderful things. Instead of accessing one key at a time, you can access a list of keys: `my %foo = ( 'one' => 1, 'two' => 2, 'three' => 3, 'four' => 4, ); print @foo{ 'one', 'two' }, "\n"; print @foo{ 'three', 'four' }, "\n";` [download] You can assign values to them too: `my %foo = (); @foo{ 'one', 'two' } = (1, 2); @foo{ 'three', 'four' } = (3, 4); print keys %foo;` [download]	[reply] [d/l] [select]
RE: RE: Merging two @ARRAYS into a %HASH by btrott (Parson) on Apr 22, 2000 at 10:23 UTC
Everything chromatic says, but also, I thought I'd add that hash slices are very useful for stuffing an array into a hash (as in the original example). For example, say that you had a list of elements and you wanted to check if certain items were in that list. The best way to do this is with a hash, generally, and it's very easy to set up such a hash for lookups: `my @list = qw/foo bar baz/; my %hash; @hash{@list} = (); # now I can test if an element is in @list # by checking if the key exists in %hash if (exists $hash{"foo"}) { print "found foo!"; }` [download]	[reply] [d/l]


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