Question about the evaluation of x = 'foo' if false

ruby-talk
1

Hello,

   I am kind of lost with the nil result while I am expecting a false:

irb(main):001:0> x = 'foo' if false
=> nil
irb(main):002:0> x
=> nil
irb(main):003:0> x = 'foo' if true
=> "foo"
irb(main):004:0> x
=> "foo"

   Thanks in advance for sharing your knowledge,

···

--
Anìbal Rojas

2

See Programming Ruby: The Pragmatic Programmer's Guide
'if' doesn't return the logical value it evaluates, it returns the
value of the last statement
executed, in the false case nothing is executed, and nil is Ruby's
nothing value

Cheers

···

On Mar 17, 12:01 pm, Aníbal Rojas <anibalro...@gmail.com> wrote:

Hello,

I am kind of lost with the nil result while I am expecting a false:

irb(main):001:0> x = 'foo' if false
=> nil
irb(main):002:0> x
=> nil
irb(main):003:0> x = 'foo' if true
=> "foo"
irb(main):004:0> x
=> "foo"

Thanks in advance for sharing your knowledge,

--
Anìbal Rojas

3

Another way to think about it is that the above constructs are
alternate ways of expressing the following:

if false then x = 'foo' end
if true then x = 'foo' end

-- Mark.

···

On Mar 17, 12:01 pm, Aníbal Rojas <anibalro...@gmail.com> wrote:

Hello,

I am kind of lost with the nil result while I am expecting a false:

irb(main):001:0> x = 'foo' if false
=> nil
irb(main):002:0> x
=> nil
irb(main):003:0> x = 'foo' if true
=> "foo"
irb(main):004:0> x
=> "foo"

Thanks in advance for sharing your knowledge,

4

Thanks for your responses!

···

--
Aníbal

On Mar 18, 2:44 pm, Mark Thomas <m...@thomaszone.com> wrote:

On Mar 17, 12:01 pm, Aníbal Rojas <anibalro...@gmail.com> wrote:

> Hello,

> I am kind of lost with thenilresult while I am expecting a false:

> irb(main):001:0> x = 'foo'iffalse
> =>nil
> irb(main):002:0> x
> =>nil
> irb(main):003:0> x = 'foo'iftrue
> => "foo"
> irb(main):004:0> x
> => "foo"

> Thanks in advance for sharing your knowledge,

Another way to think about it is that the above constructs are
alternate ways of expressing the following:

iffalse then x = 'foo' endiftrue then x = 'foo' end

-- Mark.