Python error explained
UnboundLocalError: what it means and how to fix it
A function changes a variable it can only see from outside.
The message
UnboundLocalError: cannot access local variable 'count' where it is not associated with a valueWhat it means
If a function assigns to a name anywhere inside it, Python treats that name as local to the function. So count += 1 tries to read a local count that has not been set yet. The cleanest fix is to pass values in and return the result.
Common causes
- Changing a global variable inside a function
- A counter or total kept outside the function that uses it
Example that raises it
count = 0
def add_point():
count += 1
add_point()
add_point()
print("Points:", count)
The fix
count = 0
def add_point(count):
return count + 1
count = add_point(count)
count = add_point(count)
print("Points:", count)
Tip: Pass values into functions and return new ones. You can use the global keyword, but code that avoids it is easier to test and reason about.
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