From: Nick Woolley <nickwoolley@...>
Date: 2005-05-04T07:12:46+09:00
Subject: mapping an array to a hash?

Hi,

Can anyone suggest an idiomatic ruby equivalent to this perl snippet?

   my %index = map { $_ => compute_something($_) } @files;

Where @files is an array of filenames, and compute_something is a 
subroutine which does some probably expensive operation on the file.

The result is a hash indexing the file name to the computed result for 
that file.  This and it's grep equivalent is something I find quite 
quite handy in perl.

The best I came up with so far seems reletively clunky to me:

   index = Hash.new()
   files.each {|f| index[f] = compute_something(f) }

or:

   index = files.inject(Hash.new) {|i,f| i[f] = compute_something(f); i }

I was wondering if there's a more succinct and readable way?

TIA,

Nick