Splitting python and calculating depending on received variable

Question

I recently posted a question about splitting a string when a character is instanced. I have come up with the following code to calculate cartesian coordinates. However, I am getting the error - 'TypeError: 'bool' object is unsubscriptable' -. How do I fix this?

add_x                    =   "s1"
add_y                    =   "a3"
sample                   =   ("0-0")
coordslst                =   sample.split('-')
user_coordinate_x        =   coordslst[0]
user_coordinate_y        =   coordslst[1]
if    (add_x.split('s'))[0] == ("s"):
    new_coordinate_x    =   str(int(user_coordinate_x) - int((add_x.split('a', 's'))[1]))
elif (add_x[0] == ('a'))[0] == ("a"):
    new_coordinate_x    =   str(int(user_coordinate_x) + int((add_x.split('a', 's'))[1]))
if    (add_y.split('s'))[0] == ("s"):
    new_coordinate_y    =   str(int(user_coordinate_y) - int((add_y.split('a', 's'))[1]))
elif  (add_y.split('a'))[0] == ("a"):
    new_coordinate_y    =   str(int(user_coordinate_y) + int((add_y.split('a', 's'))[1]))
new_coordinates     =   new_coordinate_x + "-" + new_coordinate_y
print new_coordinates

Answer 1

It's this line here

elif (add_x[0] == ('a'))[0]:

(add_x[0] == ('a')) returns False

and you are trying to access it's first element like False[0], which doesn't make sense.