From: Jacob Fugal <lukfugl@...>
Date: 2006-02-03T08:10:04+09:00
Subject: Re: Seeking the Ruby way

On 2/2/06, ara.t.howard@noaa.gov <ara.t.howard@noaa.gov> wrote:
>    require "csv"
>    require "yaml"
>
>    path = ARGV.shift
>    sum = Hash::new{|h,k| h[k] = 0}
>    count = lambda{|row| sum[row.last.to_s[0,6]] += 1}
>    CSV::open(path,"r"){|row| count[row]}
>    y sum.delete_if{|k,v| v == 1}

I'm curious why you decided to make `count` its own lambda when:

  1) It's only ever used once
  2) The block that uses it has only one statement, namely the call to `count`
  3) count and the block to CSV::open have the same signature

I think at a minimum, given 2) and 3), I'd just replace the block to
CSV::open with count itself:

  count = lambda{|row| sum[row.last.to_s[0,6]] += 1}
  CSV::open(path,"r", &count)

Then, since count isn't used anywhere else, I'd join those together:

  CSV::open(path,"r"){|row| sum[row.last.to_s[0,6]] += 1}

After those transformations:

  galadriel:~ lukfugl$ cat a.rb
  require "csv"
  require "yaml"

  path = ARGV.shift
  sum = Hash::new{|h,k| h[k] = 0}
  CSV::open(path,"r"){|row| sum[row.last.to_s[0,6]] += 1}
  y sum.delete_if{|k,v| v == 1}

  galadriel:~ lukfugl$ cat in.csv
  0,aaaaaa___
  1,aaaaaa___
  2,aaabbb___
  3,aaabbb___
  4,aaabbb___
  5,aaaccc___

  galadriel:~ lukfugl$ ruby a.rb in.csv
  ---
  aaaaaa: 2
  aaabbb: 3

Just seems a little clearer to me over having an extra one-time use lambda.

Jacob Fugal