Ruby: What is the easiest method to update Hash values?

Question

Say:

h = { 1 => 10, 2 => 20, 5 => 70, 8 => 90, 4 => 34 }

I would like to change each value v to foo(v

Answer 1

The following is slightly faster than @Dan Cheail's for large hashes, and is slightly more functional-programming style:

new_hash = Hash[old_hash.map {|key, value| key, foo(value)}]

Hash#map creates an array of key value pairs, and Hash.[] converts the array of pairs into a hash.