gistfile1.rb

require 'benchmark'

class Validated
  def valid?
    true
  end
end

c1 = [Validated.new]
c10 = c1 * 10
c100 = c1 * 100

[c1, c10, c100].each do |c|
  Benchmark.bm(12) do |bm|
    bm.report("collect %4d" % [c.size]) { 100_000.times { c.collect { |r| r.nil? || r.valid? }.all? } }
    bm.report("inject  %4d" % [c.size]) { 100_000.times { c.inject(true) { |v, r| (r.nil? || r.valid?) && v } } }
  end
end

#                   user     system      total        real
# collect    1  0.140000   0.000000   0.140000 (  0.150392)
# inject     1  0.200000   0.000000   0.200000 (  0.203541)
#                   user     system      total        real
# collect   10  0.700000   0.010000   0.710000 (  0.719507)
# inject    10  1.070000   0.000000   1.070000 (  1.087400)
#                   user     system      total        real
# collect  100  6.090000   0.030000   6.120000 (  6.216200)
# inject   100  9.800000   0.040000   9.840000 ( 10.333687)