UnboundLocalError: local variable 'r' referenced before assignment

Question

I'm having an issue with variable and function. Here is a simple code:

r = 0
list = ['apple','lime','orange']
def list_list(x):
    for i in x:
        r +=1
        print r
list_list(list)

Error:

UnboundLocalError: local variable 'r' referenced before assignment

I know it must be something simple. I started to do my script using functions instead straight code.

What is this function supposed to do? Your error is that r is global (not local) but I can't tell you how to fix it without knowing the intended behavior of the program. — ApproachingDarknessFish, Mar 12 '13 at 23:29
There are probably 100 questions on SO about this. Ever tried google? — JBernardo, Mar 12 '13 at 23:32

score 3 · Accepted Answer · answered Mar 12 '13 at 23:26

You should rewrite your function to take r as an argument if you want to define it outside of your function:

def my_func(some_list, r=0):
    # do some stuff

Basically, you have a problem with scope. If you need r outside of the function, just return it's value in a tuple:

def my_func(some_list, r=0):
    # do some stuff

    return new_list, r

my_list = [1,2,3,4,5]
different_list, my_outside_r = my_func(some_list, 0)

score 2 · Answer 2 · edited Mar 12 '13 at 23:29

2

The r within the function isn't the same as the one outside the function, so it hasn't been set yet.

edited Mar 12 '13 at 23:29

answered Mar 12 '13 at 23:26

Peter Wooster

jurgenreza · Answer 3 · 2013-03-12T23:31:46.360

1

You shoudld put r = 0 inside the function. But if you want the length of the list just use len(list)

Also try to avoid naming variables same as builtin names like list.

edited Mar 12 '13 at 23:31

answered Mar 12 '13 at 23:26

jurgenreza