Re^4: Convert a string into a hash

There is no information in a hash with index values that isn't in an array.

Yes and no. If you want to know "the position of a given number", the information is there in the array, but finding it is hard (O(N)). It's O(1) with a hash.

my ($index) = grep $code[$_] == $x, 0..$#code;

   -vs-

my $index = $code{$x};
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Re^5: Convert a string into a hash by Your Mother (Archbishop) on Aug 15, 2009 at 04:27 UTC
NIce comparison/example of a possible why. With `List::Util::first`, or equivalent code, you could at least move the array more to the middle ground (on average); I know you know that already and it's good (for me at least) to be confronted with the algorithm costs. That alone suggests a reason for doing it with the hash.	[reply] [d/l]
Re^6: Convert a string into a hash by ikegami (Patriarch) on Aug 15, 2009 at 15:52 UTC
you could at least move the array more to the middle ground (on average) Pretending for a second that `first` doesn't require putting the contents of entire array on the stack, the performance would still be O(N). Mind you, that's rarely a problem since most arrays are quite small, but the code is also much less readable.	[reply] [d/l]