Zach Carter Predictably Meta

Removing duplicate characters

An interesting string method was brought to my attention on the ruby-talk mailing list: string.squeeze. It removes duplicate characters in a string, and performs better than regular expressions or splitting-joining, to boot. Craig posted some benchmarks:

require 'benchmark'

n = 1_000_000

Benchmark.bm(10) do |x|
 x.report("gsub") { n.times do
    "This     is  a test   string.".gsub(/ +/, ' ')
  end
 }
 x.report("gsub!") { n.times do
    "This     is  a test   string.".gsub!(/ +/, ' ')
  end
 }
 x.report("split.join") { n.times do
    "This     is  a test   string.".split.join(' ')
  end
 }
 x.report("squeeze.strip") { n.times do
    "This     is  a test   string.".squeeze(' ').strip
  end
 }
end

               user     system      total        real
gsub        4.470000   0.040000   4.510000 (  4.578173)
gsub!       4.390000   0.020000   4.410000 (  4.468695)
split.join  3.500000   0.020000   3.520000 (  3.556669)
squeeze.strip  1.980000   0.010000   1.990000 (  2.003622)

Nice!