Why postfix `if` in Ruby works so strange

Question

I have strange behavior in Ruby:

var1.zero? if var1 = 1

NameError

: undefined local variable or method var1

for main: Object

On the other hand, if I do the same in standard if

, everything works as expected:

if var1 = 1
  var1.zero?
end
# => false

Can anyone describe how postfix works if

in Ruby?

+3

user3240646 Jul 28 17 at 14:55

2 answers

ndn · Answer 1 · 2017-07-28T15:06:28+0000

Because if I ask you

Not my darling daughter ...

you interrupt me with

Do you have a daughter?

before I could finish my initial sentence, which was

Not my daughter is cute, is that her [display photo]?

But if I ask you

[showing the image] This is my daughter, isn't she cute?

you can answer easily

Not

Pardeep dhingra · Answer 2 · 2017-07-28T15:00:03+0000

It will go from left to right, first it will read var1.zero?

and thenif var1 = 1

var1.zero? if var1 = 1

why will he get var1

NameError: undefined local variable or method `var1 'for main: Object

And here,

if var1 = 1
  var1.zero?
end

var1 = 1

will create var1 with value 1, so its error will not be thrown. when its execution var1.zero?

.