trim.rb

require 'benchmark'

N = 50000
STRING = "asd sda sda sd"

Benchmark.bm do |b|
  b.report('gsub, s') do
    N.times { STRING.gsub(/\s/, '') }
  end
  b.report('gsub, s+') do
    N.times { STRING.gsub(/\s+/, '') }
  end
  b.report('gsub, space') do
    N.times { STRING.gsub(' ', '') }
  end
  b.report('split.join') do
    N.times { STRING.split.join }
  end
  b.report('delete') do
    N.times { STRING.delete(' ') }
  end
end

---------------------------------------

       user     system      total        real
gsub, s  0.110000   0.000000   0.110000 (  0.108990)
gsub, s+  0.110000   0.000000   0.110000 (  0.111848)
gsub, space  0.130000   0.000000   0.130000 (  0.127770)
split.join  0.060000   0.000000   0.060000 (  0.059390)
delete  0.030000   0.000000   0.030000 (  0.030618)