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

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, Oct 31 '20 at 14:43
It wouldn't enter elif condition when it has entered if condition. — jizhihaoSAMA, Oct 31 '20 at 14:43
Does this answer your question? [Python 3: UnboundLocalError: local variable referenced before assignment](https://stackoverflow.com/questions/10851906/python-3-unboundlocalerror-local-variable-referenced-before-assignment) — Sabito stands with Ukraine, Oct 31 '20 at 14:51
@Carcigenicate , is there a way to sort of 'bring the value of 'a'? Something like assigning a permanent value for 'a'? — Choripán Con Pebre, Oct 31 '20 at 14:54

score 1 · Answer 1 · answered Oct 31 '20 at 14:47

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.

score 0 · Answer 2 · answered Oct 31 '20 at 14:48

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.

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

2 Answers2