Error in code: TypeError: can't multiply sequence by non-int of type 'float'

Question

I am using this simple python script that defines two functions that calculate the area and volume of a cylinder, given its radius and height:

import math

def calculate_area(radius):
    area = math.pi * radius ** 2
    return area

def calculate_volume(radius, height):
    volume = calculate_area(radius) * height
    return volume

r = 5
h = "10"
volume = calculate_volume(r, h)
print("The volume of the cylinder is:", volume)

When I execute the script, I see the following error:
TypeError: can’t multiply sequence by non-int of type ‘float’

I have tried Importing the float() function instead of the math module, but it only gives more errors. can somebody help me with this? Thanks.

Asked By: Kirs

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Source

Answer 1

The ‘h’ variable in your code is defined as a string rather than a number.
You must first use the float() function to convert the h variable to a number before passing it to the calculate_volume() function:

import math

def calculate_area(radius):
    area = math.pi * radius ** 2
    return area

def calculate_volume(radius, height):
    volume = calculate_area(radius) * height
    return volume

r = 5
h = "10"
volume = calculate_volume(r, float(h))
print("The volume of the cylinder is:", volume)

Answered By: Alon Alush

Answer 2

Your h is a str (so it’s a sequence actually) and your calculated area is a float, so python cannot multiply them. Your h should be an int/float.

import math

def calculate_base_area(radius:float)->float:
    area = math.pi * radius ** 2
    return area

def calculate_volume(*,radius: float, height:float)->float:
    volume = calculate_base_area(radius) * height
    return volume

r = 5
h = 10
volume = calculate_volume(radious=r,height=h)
print("The volume of the cylinder is:", volume)

Side notes

calculate area does not calculate area of the cyllinder, rather its base area, so I’d suggest renaming to avoid confusion later on. The area would be 2*pi*r*h+2*pi*r**2 (side area+2 base areas)
use type hints, this will make your IDE tell you about this kind of mistakes before running the code
when the order of the parameters matters it’s good to enforce using keyword arguments in your function (this will prevent using height and radious interchangeably which would lead to errors)
if invalid arguments can be passed to your function use try...carch inside to handle that

Answered By: Gameplay

Answer 3

your h is string , for that not working.

Answered By: Amir.q.a

Error in code: TypeError: can't multiply sequence by non-int of type 'float'

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