Comments on: Finding word frequencies using Erlang

By: Word frequency redux – Erlang list comprehension, regex and list folding « Robert Horvick

Thu, 02 Jul 2009 21:28:21 +0000

[...] Cribbs was nice enough to point out a pair of changes I could make to my word frequency counter from last [...]

By: Robert

Robert — Thu, 02 Jul 2009 20:14:51 +0000

@Sean Thanks! The re module certainly is an improvement. I need to think more about lists:foldX. lists:foldl(fun(W, Dict) -> dict:update(W, fun(C) -> C + 1 end, 1, Dict) end, dict:new(), ["foo", "foo", "bar"]). Edit: I said the above didn't work but in fact it did. I was looking at the output in erl and forgettting the output is a dict, not a list.

By: Sean

Sean — Thu, 02 Jul 2009 14:15:26 +0000

While there’s nothing “wrong” with your code, per se, a suggestion – Erlang now has PCRE-style regular expressions, and the ‘regexp’ module is being deprecated.

So you could capture all of the words in the string with something like this:

words(String) ->
  {match, Captures} = re:run(String, "\\b\\w+\\b", [global,{capture,first,list}]),
  [hd(C) || C<-Captures]. % re returns the capture as a nested list

Then I’d probably use some kind of key-value structure, like a proplist or dict, to count the words using a lists:foldX function.