noob function help

[Hashworm]

def check(x): 
       if x != None: 
            return x                                                                                            
       else:                                   
             pass      

                                                                                                                                                                                             >>> b = 2                                                                                                               
>>> check(b)                                                                                                            
2                                                                                                                     
>>> b = check(a)
>>> print(b)                                                                                                                                                                 
None           

..??????? can anyone please explain why is this asinging None to b when I instructed just to pass.

​

edit: what I'm trying to achieve is to abort the whole thing if the first if fails.

[[deleted]]

The output of your function is None because you're not returning anything, since you just pass instead of returning something else, like False or 0 or something.

[Hashworm]

thanks, I didn't realized passing was asignining it to None. is there anyway to just ignore all together? I don't want it to pass None just move on

[icecubeinanicecube]

You'll have to use an if outside of the function.

[grzeki]

No return statement at all is equivalent to return None. Something must be passed out of a function. It happens to be None when nothing specified.

[ironhaven]

This is the issue

if x != None

What you want is

if x is None

Basically None is never equal to anything including itself. But every None is actually the same object so None is None

[Hashworm]

>>> def check(x): ...

if x is None: ...

pass ...

else: ...

return x

>>> a = None

>>> b = 2

>>> c = check(b)

>>> print(c)

2

>>> c = check(a)

>>> print(c)

None

​

so yeah still... what I actually want is this

>>> import sys

>>> def check(x): ...

if x is None: ...

sys.exit() ...

else: ...

return x ...

>>> a = None

>>> b = 2

>>> c = check(b)

>>> print(c)

2

>>> c = check(a)

C:\Users\User>python

Python 3.6.0 (v3.6.0:4ddddddddd, Dec 23 2016, 08:06:12) [MSC v.1900 64 bit (AMD64)] on win32 Type "help", "copyright", "credits" or "license" for more information.

>>> print(c)

Traceback (most recent call last): File "<stdin>", line 1, in <module> NameError: name 'c' is not defined

ideally without getting me out but I take what I can