From: "Charles L. Snyder" <clsnyder@...>
Date: 2007-02-08T05:55:15+09:00
Subject: histogram of histograms

Hi

I have several text files that look like this:

Brazil,	10
Brazil,	13
Brazil,	9
Bulgaria, 1
Canada, 48
Canada, 52
Canada, 38
Canada, 55
Canada, 59
Chile, 1
Chile, 1
Chile, 2
China, 7
China, 18
China, 19
China, 22
China, 25

I need to iterate through the above file(s) and get the data
summarized in the form:

Canada, 252
China, 91
Chile, 4
Brazil, 32
Bulgaria, 1

I know how to go from a single column list with multiple repeated
values to a 'histogram' type list, ie:

my_hash = countries.inject(Hash.new { 0 }) { |counts, key| counts[key]
+= 1; counts}
my_hash = my_hash.sort { |a,b| a[1] <=> b[1] }

but I'm unable to figure out how to get the 2-column csv values into a
total by country as shown above.
(I do have another file "countries.txt" which is a unique list of
countries.)

Thanks in advance!

CLS