Syntax error at second definition in Python

Question

def specificChecker(someThing, checker):
    if checker == None:
        return someThing
    elif checker == True:
        return not someThing
    else:
        return None

def whatDoesTheCheckerSay(someThing):
    if specificChecker(someThing) == someThing:
        return 'The checker value was False on that one.'
    elif specificChecker(someThing) == not someThing:
        return 'The checker value was True on that one.'
    elif specificChecker(someThing) == None:
        return 'Something irregular happend. The checker value wasn\'t None or True.'
    else:
        return 'Something went really wrong. This doesn\'t even not work.'

reallySomeThing = input('Type in really some thing: ')
theChecker = input('Set the checker to something: ')

print(specificChecker(reallySomeThing, theChecker))
print(whatDoesTheCheckerSay(reallySomeThing)) # This can be made more efficient, right?

def one(someShit):
    return someShit + ' AWWW YEAH!'

def two(someShit):
    return one(someShit)

print(two(input('Type in some kind of stuff: ')))

I'm a self-taught beginner, so surely it's something awkwardly basic. I'm using the IDLE shell and have repeatedly gotten a syntax error at the second definition statement of my codes. Please help?

its the `== not something`, it should be `!= something` or `is not something` — nbryans, Jun 23 '16 at 13:02
@nbryans: Really bad idea to mention `is` and just say "similar to `==`". `is` means identity testing; `x is y` only if `x` and `y` are references to the exact same object. In general, you only use `is` with language specified singletons (`None`, `NotImplemented`, `Ellipsis`, but not `True`/`False`, even though they're singletons, PEP8 recommends implicit truth testing for good reasons), types (if you want an instance of a specific class, but not subclasses thereof, `type(obj) is MyClass`), and sentinels (`sentinel = object(); val = mydict.get(key, sentinel); if val is not sentinel:`). — ShadowRanger, Jun 23 '16 at 15:20

Noel Evans · Accepted Answer · 2016-06-23T13:52:22.187

4

You cannot use the line:

elif specificChecker(someThing) == not someThing:

This must be written

elif specificChecker(someThing) != someThing:

to be valid Python.

This is also valid but is perhaps less readable:

elif (specificChecker(someThing)) == (not someThing):

After OP edit:

The new error is the mismatch in arguments (always 1) to a function that requires 2 arguments. You have to pass two arguments to specificChecker not one

edited Jun 23 '16 at 13:52

answered Jun 23 '16 at 13:01

Noel Evans

8,113
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I have been using Python for many years and never knew that. Is it documented somewhere that `== not` is a SyntaxError? – RemcoGerlich Jun 23 '16 at 13:24
I assume it comes from this: https://docs.python.org/2/reference/expressions.html#not-in – Noel Evans Jun 23 '16 at 13:40
The `==` comes before `not` in the operators so I assume takes precedence. – Noel Evans Jun 23 '16 at 13:41

Wokpak · Answer 2 · 2016-06-23T13:09:15.570

2

Line 12: elif specificChecker(someThing) == not someThing:

If you want to check if some variable is not some variable, used is not for boolean or != for values and strings

edited Jun 23 '16 at 13:09

answered Jun 23 '16 at 13:03

Wokpak

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Syntax error at second definition in Python

2 Answers2