def xdgt(x): if x is "m": a = True print(a) else: a = False print(a) x = input("Are you Male or Female? please only input m or f:") xdgt(x) print(a) Result:
Traceback (most recent call last): File "/tmp/sessions/dd8fb527f68c80d1/main.py", line 10, in print(a) NameError: name 'a' is not defined
Add a return a to your function
def xdgt(x): if x is "m": a = True else: a = False return a a = xdgt(x) print(a) 
It seems like you want the function to return the value. In which case you can change your code as follows:
def xdgt(x): if x is "m": a = True else: a = False return a x = input("Are you Male or Female? please only input m or f:") return_val= xdgt(x) print(return_val) Takeaway here:
Instead of printing the value inside the function you should return it and store it in a variable so that you can use it to perform functions you desire like printing the value in this case.
If you want to use local variable a outside of the function, use global.
def xdgt(x): global a if x == 'm': a = True else: a = False x = input("Are you Male or Female? please only input m or f:") xdgt(x) print(a) 
isto compare strings, use==. In short, your function should be written asreturn x == 'm'.