无法找出TypeError

Question

I got a (TypeError: can't multiply sequence by non-int of type 'float') error and I can't figure out how to fix it. I've searched the error and wasn't able to figure out how to fix it because the code examples that had the error didn't look like the code I'm having a problem with.

# Variable stuff
initialMagnitudes = input("What are the initial magnitudes of the 
vector? (separate with spaces)\t").split()
for string in initialMagnitudes:
    string = float(string)
initialDirections = input("What are the initial directions of the 
vector? (in degrees and separate with spaces)\t").split()
for string in initialDirections:
    string = float(string)
vector_i = []
vector_j = []
vectorEquation = "Xi + Yj"
resultantMagnitude = 0.0
resultantDirection = 0.0
resultantVectorEquation = "R = Xi + Yj"


def find_vector_equation():
    global vectorEquation
    global vector_i
    global vector_j
    for magnitude in initialMagnitudes:
        theta = 
float(initialDirections[initialMagnitudes.index(magnitude)])
        vector_i.append(math.cos(math.radians(theta))*magnitude)
        vector_j.append(math.sin(math.radians(theta))*magnitude)
        vectorEquation = "{}i + {}j".format(vector_i, vector_j)
    print("The resultant vector equation is: "+vectorEquation)
find_vector_equation()

Here is all the code that could be part of the problem. Thanks in advance for all the help!

Answer 1

This is the problem:

for string in initialMagnitudes:
    string = float(string)

This doesn't change anything in initialMagnitudes . Instead, you change the variable string to be a float version of its string value, and then throw away that float. The loop variable in a for statement is a value, not a slot in the list; it has no idea where it came from and assigning to it does not put the value back in the list.

Since the items of initialMagnitudes are still strings, trying to multiply by one of them is trying to multiply a string by a float, and you get the error you get.

Best to do it with a list comprehension:

initialMagnitudes = [float(value) for value in initialMagnitudes]