From: Phrogz <phrogz@...>
Date: 2007-11-07T01:15:16+09:00
Subject: Re: why return gives error when used with ? :

On Nov 6, 3:11 am, Shuaib Zahda <shuaib.za...@gmail.com> wrote:
> Oops I forgot to ask
> which one is faster
> if x == 5
> return true
> else
> return false
> end
>
> or the conditional operator ? :
> x == 5 ? true : false

They're about the same speed. Where you _will_ see a small performance
gain, however, is leaving off the call to the return method
altogether. The value of the last expression in a method is the return
value. The only time to use return if you need to exit a method early.
(And this practice is considered a bad idea by some people in many
situations.)

require 'benchmark'

def ternary_return1( x )
  return ( x==5 ? true : false )
end

def ternary_return2( x )
  x==5 ? (return true) : (return false)
end

def if_return1( x )
  return (if x == 5
    true
  else
    false
  end)
end

def if_return2( x )
  if x == 5
    return true
  else
    return false
  end
end

def ternary_expression( x )
  x == 5 ? true : false
end

def if_expression( x )
  if x == 5
    true
  else
    false
  end
end

values = (1..8).to_a * 500_000
method_names = %w| ternary_return1 ternary_return2
                   if_return1 if_return2
                   ternary_expression if_expression |

Benchmark.bmbm{ |x|
  method_names.each{ |name|
    meth = method( name )
    x.report( name ){
      values.each{ |n|
        meth.call( n )
      }
    }
  }
}

Rehearsal ------------------------------------------------------
ternary_return1      6.125000   0.000000   6.125000 (  6.157000)
ternary_return2      5.859000   0.000000   5.859000 (  5.906000)
if_return1           6.016000   0.000000   6.016000 (  6.047000)
if_return2           5.906000   0.000000   5.906000 (  5.953000)
ternary_expression   5.453000   0.000000   5.453000 (  5.484000)
if_expression        5.672000   0.000000   5.672000 (  5.687000)
-------------------------------------------- total: 35.031000sec

                         user     system      total        real
ternary_return1      6.047000   0.000000   6.047000 (  6.078000)
ternary_return2      6.250000   0.000000   6.250000 (  6.282000)
if_return1           6.032000   0.000000   6.032000 (  6.063000)
if_return2           6.157000   0.000000   6.157000 (  6.187000)
ternary_expression   5.656000   0.000000   5.656000 (  5.703000)
if_expression        5.750000   0.000000   5.750000 (  5.781000)