Why is 032 different than 32 in Ruby?

Question

I have noticed Ruby behaves differently when working with 032 and 32. I once got syntax errors for having 032 instead of just 32 in my code. Can someone explain this to me?

Answer 1

If you start a number with 0 (zero), ruby treats it as an octal, so you normally don't want the zero. You'll have to be more specific about the syntax error.

Answer 2

What you're seeing is 032 is an octal representation, and 32 is decimal:

>> 032 #=> 26
>> 32 #=> 32
>> "32".to_i(8) #=> 26
>> "32".to_i(10) #=> 32

And, just for completeness, you might need to deal with hexadecimal:

>> 0x32 #=> 50
>> "32".to_i(16) #=> 50

and binary:

>> 0b100000 #=> 32
>> 32.to_s(2) #=> "100000"

Answer 3

When you have a zero in front of your number, Ruby interprets it as an octal(base 8 number).

You syntax error is probably something like this:

ruby-1.9.2-p136 :020 > 08
SyntaxError: (irb):20: Invalid octal digit

Answer 4

i don't know about syntax errors, but when you prefix a number with zero it means it's octal (base-8)... so 032 is actually 26 in decimal