Python error when asking to return a variable (referenced before assignment) [duplicate]

Question

I have the following code but Python keeps saying "local variable 'a' referenced before assignment"

def inter(X,Y):
    if pertenece(cabeza(X),Y):
        a = lista(cabeza(X),inter(cola(X),Y))
    elif vacia(cola(X)): return a
    else: inter(cola(X),Y)

I have no idea why I'm getting this error since I have defined 'a' before referencing it. Please help.

The functions 'pertenece', 'cabeza', 'cola', 'vacia' and 'lista' where all previously defined and have no issue.

return a will only happen if pertenece(cabeza(X),Y) is False, but a will only be set if pertenece(cabeza(X),Y) is True. What do you want a to be when pertenece(cabeza(X),Y) is False? — Carcigenicate
– Carcigenicate, Commented Oct 31, 2020 at 14:43
It wouldn't enter elif condition when it has entered if condition. — jizhihaoSAMA
– jizhihaoSAMA, Commented Oct 31, 2020 at 14:43
Does this answer your question? Python 3: UnboundLocalError: local variable referenced before assignment — Sabito
– Sabito, Commented Oct 31, 2020 at 14:51
@Carcigenicate , is there a way to sort of 'bring the value of 'a'? Something like assigning a permanent value for 'a'? — Sebastián P. Pincheira
– Sebastián P. Pincheira, Commented Oct 31, 2020 at 14:54

Karan Keswani · Accepted Answer · 2020-10-31 14:47:25Z

1

I think this is because you're initializing var a in an if clause, and refrencing it in another if clause, so considering the condition it may or may not be initialized befored it is referenced in if clause. Can you try to initialize a within the function body before your first if clause, to a empty or null value. Maybe that could help.

answered Oct 31, 2020 at 14:47

Karan Keswani

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Comments

Jacob Lee · Accepted Answer · 2020-10-31 14:48:14Z

0

You have only defined a in the first conditional statement. If the code never goes through that condition, then a will never be defined. You would have to assign some default value for a before the conditional statements in order to prevent the return statement from throwing an error at you.

answered Oct 31, 2020 at 14:48

Jacob Lee

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