Found in the Ruby style guide.
1 > 2 ? true : false; puts 'Hi'
I assume this always returns Hi, but how do I read it?
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Note: I understand the terneary operator (? :). The part that confuses me is ; puts "Hi"Evan V– Evan V2012-10-03 02:55:03 +00:00Commented Oct 3, 2012 at 2:55
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It is a bad example. It does not mean much.sawa– sawa2012-10-03 03:04:40 +00:00Commented Oct 3, 2012 at 3:04
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To expand on @sawa's comment, it was listed as an example after saying to use spaces after semicolons, and when to use spaces for other syntax. It's probably contrived because there's rarely a good reason to use semicolons - it's the only place in the style guide that mentions semicolons.Andrew Grimm– Andrew Grimm2012-10-03 22:25:43 +00:00Commented Oct 3, 2012 at 22:25
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6 Answers
If 1 > 2 then true, else it is false.
However, it will print hi whatever the condition result.
It is the same that:
if 1 > 2 then
true
else
false
end
puts 'hi'
1 Comment
Evan V
Thanks. Looks like I was overthinking this one.
You may read this like
1 > 2 ? true : false # first line of code
puts "Hi" #second line of code
Comments
The Ruby compiler reads it like this:
1.>( 2 )
puts "Hi"
Ternary operator ? : is redundant. Comparison 'greater than' symbol :> is actually a method of Numeric class.
Comments
If 1 is greater than 2 then true, else then false. Then puts Hi
Comments
The semicolon is an inline way of separating two lines of code. So it's just like
1 > 2 ? true : false
puts "Hi"
which is equivalent to
false
puts "Hi"
And of course a line that just says false will do nothing (except for a few cases, like if it's the last line of a function definition in which case the method returns false if it reaches that line).
Comments
1 > 2 ? true : false; puts "Hi" that means
if 1 > 2
return true
else
return false
end
puts "Hi"
Here each time means the result is whatever it will print "hi" because we print "Hi" in outside of condition.
but
if 1 > 2
puts "1 is not greater than 2"
else
puts "1 is greater than 2"
end
you can also test in your console
1.9.3p125 :002 > if 1 > 2
1.9.3p125 :003?> puts "1 is not greater than 2"
1.9.3p125 :004?> else
1.9.3p125 :005 > puts "1 is greater than 2"
1.9.3p125 :006?> end
1 is greater than 2
=> nil
