Confusion with Ruby printing mechanics

ruby-talk
1

Here I just played to see how printing statement behaves with "nil"
values. Here we go:

p nil

nil
=> nil #good as expected.

puts nil

       #as nil.to_s causes the "blank" in the first line.
=> nil #good as expected.

p puts nil

    #as nil.to_s causes the "blank" in the first line
nil
=> nil # good as expected, as p works here on the return value of puts.

···

=========================

Confusion begins with the below :

p(puts(print("hi")))

hi
nil
=> nil # this is the actual output.

But from the above analysis I expected the below:

p(puts(print("hi")))

hi

nil
=> nil

Could you explain the gap between my assumption and the actual one?

Thanks.

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2

Print doesn't append a newline, so the puts'd nil is tacked onto the end of
the 'hi'

I'd write more, but I hate typing on my phone.

···

Sent from my phone, so excuse the typos.
On Feb 16, 2013 8:42 PM, "Love U Ruby" <lists@ruby-forum.com> wrote:

Here I just played to see how printing statement behaves with "nil"
values. Here we go:

>> p nil
nil
=> nil #good as expected.
>> puts nil
       #as nil.to_s causes the "blank" in the first line.
=> nil #good as expected.
>> p puts nil
    #as nil.to_s causes the "blank" in the first line
nil
=> nil # good as expected, as p works here on the return value of puts.

=========================

Confusion begins with the below :

>> p(puts(print("hi")))
hi
nil
=> nil # this is the actual output.

But from the above analysis I expected the below:

>> p(puts(print("hi")))
hi

nil
=> nil

Could you explain the gap between my assumption and the actual one?

Thanks.

--
Posted via http://www.ruby-forum.com/\.

3

Confusion begins with the below :

p(puts(print("hi")))

hi
nil
=> nil # this is the actual output.

But from the above analysis I expected the below:

p(puts(print("hi")))

hi

nil
=> nil

Well there you are adding only one newline, it's added with puts. You
can find what you want also in this way:

p print("hi\n\n")

···

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4

why do you have confusion?? didnt they already told you how the print
commands work?

in your sample:
print("hi") does "hi" and returns nil
puts(nil) does "\n" and returns nil
p(nil) does "nil\n" and returns nil (the object it gets)

was it that hard to get??

···

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5

Matthew Kerwin wrote in post #1097228:

Print doesn't append a newline, so the puts'd nil is tacked onto the end
of
the 'hi'

I'd write more, but I hate typing on my phone.

Sent from my phone, so excuse the typos.

Humm! perfect catch tried and tested. and you got 100 out of 100. :slight_smile: :slight_smile:

p(puts(print("hi\n")))

hi

nil
=> nil

···

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6

Damián M. González wrote in post #1097245:

Confusion begins with the below :

Well there you are adding only one newline, it's added with puts. You
can find what you want also in this way:

p print("hi\n\n")

I actually had confusion with the below:

p(puts(print("hi")))

hi
nil
=> nil # this is the actual output.

how it comes? to catch this i added one '\n'.

···

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7

Hans Mackowiak wrote in post #1097261:

why do you have confusion?? didnt they already told you how the print
commands work?

in your sample:
print("hi") does "hi" and returns nil
puts(nil) does "\n" and returns nil
p(nil) does "nil\n" and returns nil (the object it gets)

was it that hard to get??

Nopes! friend... I am set at all. I just told him,what made me confused.

Thanks

···

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