[Type B] Working with Functions – Chapter 3 Sumita Arora

7. Predict the output of the following code:

a = 10
y = 5
def myfunc():
    y = a
    a = 2
    print("y =", y, "a =", a)
    print("a+y =", a + y)
    return a + y
print("y =", y, "a =", a)
print(myfunc())
print("y =", y, "a =", a)

Solution: Though, this code will result in an UnboundLocalError because the variable a is referenced before assignment inside the function myfunc.

The initial print statement print("y =", y, "a =", a) outside the function myfunc() also executes correctly, showing y = 5 and a = 10. However, when the myfunc() function is called, it raises an UnboundLocalError.

Therefore, the execution of the script stops prematurely, and the final print statement is not reached. Here’s the output in the console.

y = 5 a = 10
Traceback (most recent call last):
  File "example.py", line 11, in <module>
    print(myfunc())
  File "example.py", line 5, in myfunc
    y = a
UnboundLocalError: local variable 'a' referenced before assignment