Question

Following are the simple statements in the irb shell. What does nilin the output mean ? Why does it accompany the print statement in the if block ?

irb(main):062:0> if(x==20 && y==30)
irb(main):063:1> print("if statement working !")
irb(main):064:1> else
irb(main):065:1* print("else statement working !!")
irb(main):066:1> end
if statement working !=> nil # what does nil represent here ?

Answer 1

In Ruby, all expressions return values, even if it’s nil. Blocks and methods simply return the value of the last expression evaluated. There are many ways to use this effectively. For example, this is the reason explicit returns are often not used. Also, you can do this:

print if x == 20 && y == 30
  'if statement working!'
else
  'else statement working!'
end

Regarding your example: in addition to printing the string as you instructed, irb will display the value it received from the if-else blocks. Since print always returns nil, both branches will return the same value.