simple ruby question

rubyonrails-talk
1

I am learning Ruby and when I am trying to work on some sample examples I got some strange (may be to me) output can you please explain me why it is ??

(1 ** 2).to_s *2 is giving output as “1” but

(1 ** 2).to_s * 2 is giving output as “11”

the above things that I tried in irb shell

2

(1 ** 2).to_s *2 is giving output as "1"

but

(1 ** 2).to_s * 2 is giving output as "11"

(1**2).to_s results in 1.to_s *2 gives "1" becoz it is interpreted as radix that is representation of 1 in base 2 the other bit is pretty simple i mean the output as "11" I hope that clears your question

3

But when I tried with “1” *2 it is giving output as “11” and the same output I am getting even I tried with “1” *2.

Can you please explain me clearly. I am NOT getting…

4

the * is both a “unary unarray” operator and a binary multiplication operator.

*2 is parsed as the former: (1 ** 2).to_s(*2)

  • 2 is parsed as the latter: (1 ** 2).to_s() * 2

-Rob

5

I would agree with bob but basically when you take a look at source code of that then i figured out that if * is not passed even then it would behave in the same way. (1**2).to_s(2) this would still give 1 but there is some wierd thing going on with to_i when you say "3".to_i(10) outputs 3 with base 10 which is as expected but if you say "3".to_i(2) outputs 0 rather than binary representation of 3. any idea??

6

But 2 is not an array. Is it being coerced into a single element array to allow the 'unary unarray' to proceed w/o error?

7

I would agree with bob but basically when you take a look at source code of that then i figured out that if * is not passed even then it would behave in the same way. (1**2).to_s(2) this would still give 1 but there is some wierd thing going on with to_i when you say "3".to_i(10) outputs 3 with base 10 which is as expected but if you say "3".to_i(2) outputs 0 rather than binary representation of 3. any idea??

str.to_i(base) says to interpret 'str' as a representation of a number
in base 'base'. Since "3" doesn't contain any valid base 2 digits
[0,1], the value is 0 (just like with "hello".to_i)

You're looking at Numeric#to_s and String#to_i

-Rob