Fill as list (with conditions).

[EmericCrue]

Hello ! =)

I'm new is Python. I would like create a function which is responsible for filling a list with 0, 1, -1 values depending on 4 other list values. I wrote a code, but it doesn't work, I don't understand why. Any of your help is welcome. Thank you!

# Position function

def Startegy(A, B, C, D):

# Create a vector of positions

    position = []
    position.append(0)

# If previous position is 0
    for i in A:
        if position(i-1) == 0:
            if A(i) > B(i) > C(i) > D(i):
                position(i) == 1
            if A(i) < B(i) < C(i) < D(i):
                position(i) ==-1
# If previous position is -1
        elif position(i-1) == -1:
            if A(i) > B(i) > C(i) > D(i):
                position(i) == 1
            if A(i) < B(i) < C(i) < D(i):
                position(i) == -1
# If previous position is 1
        elif position(i-1) == 1:
            if A(i) > B(i) > C(i) > D(i):
                position(i) == 1
            if A(i) < B(i) < C(i) < D(i):
                position(i) == -1
# In other case keep the position
        else:
            position(i) == position(i-1)
    
    return position

A = [1,5,6,9,10,15]
B = [1,4,5,8,12,10]
C = [1,3,4,7,8,6]
D = [1,2,3,4,5,5]

res = Startegy(A,B,C,D)

print(res)