How to Fix TypeError: Can’t Multiply Sequence by non-int of Type ‘float’ In Python?

✯ Overview

Problem: Fixing TypeError: Can’t Multiply Sequence by non-int of Type ‘float’ in Python.

Example: Consider that you want to calculate the circumference of a circle using the radius entered by the user, as shown below.

As you can see above, we encountered a TypeError while executing our code.

Bugs like these can be really frustrating!😡 But, after you finish reading this article, these silly bugs will no longer be a matter of concern for you. Therefore, to understand what causes such errors and how to avoid them, it is important to answer a few questions:

  • What is a TypeError in Python?
  • Why does Python raise TypeError: Can’t Multiply Sequence by non-int of Type ‘float’ ?
  • How do we fix TypeError: Can’t Multiply Sequence by non-int of Type ‘float’ ?

Let’s dive into each question one by one.

✯ What is TypeError in Python?

Python raises a TypeError when you try to use a function or call an operator on something that is of the incorrect type.

Example:

print('Python'+3.8)

Output:

Traceback (most recent call last):
  File "D:/PycharmProjects/PythonErrors/TypeError Can’t Multiply Sequence by non-int of Type ‘float’ In Python.py", line 1, in <module>
    print('Python'+3.8)
TypeError: can only concatenate str (not "float") to str

⮞ We encountered the above error because Python expects the + operator between two numeric types. However, in the above example we tried to add a string and a float value. Thus, Python throws a TypeError, saying us that one of the parameters was of incorrect type.

This brings us to the next question!

✯ Why does Python raise – ‘TypeError: can only concatenate str (not “float”) to str‘ ?

Python allows multiplication of a string and a float value. This means it generates a repeating sequence of the string such that the given string value is repeated as many times as mentioned as the integer value.

Example:

print('Finxter '*5)

Output:

Finxter Finxter Finxter Finxter Finxter

🤔 But, can you multiply a floating value and a string value in Python?

Answer: No, you cannot multiply a string value and a float value in Python. You will get TypeError: can't multiply sequence by non-int of type 'float' if you try to do so.

Example:

radius = input("Enter the radius: ")  # string input
print('Circumference = ', 2 * 3.14 * radius)

Output:

Enter the radius: 5
Traceback (most recent call last):
  File "D:/PycharmProjects/PythonErrors/TypeError Can’t Multiply Sequence by non-int of Type ‘float’ In Python.py", line 2, in <module>
    print('Circumference = ',2*3.14*radius)
TypeError: can't multiply sequence by non-int of type 'float'

Solution: Please go through this solution only after you have gone through the scenarios mentioned below.

radius = float(input("Enter the radius: "))
print('Circumference = ', 2 * 3.14 * radius)
# OUTPUT:
 # Enter the radius: 5
 # Circumference =  31.400000000000002

➥ Similarly, whenever you try to multiply a float value and a sequential data-type (string/tuple/lists), Python will raise a TypeError: can’t multiply sequence by non-int of type ‘float’.

Example:

my_list = [100, 200, 300, 400]  # list
my_tup = (9, 99, 999, 9999, 99999)  # tuple
print(2.0 * my_list)
print(2.0 * my_tup)

# DESIRED OUTPUT:
# [100, 200, 300, 400, 100, 200, 300, 400]
# (9, 99, 999, 9999, 99999, 9, 99, 999, 9999, 99999)

Output:

Traceback (most recent call last):
  File "D:/PycharmProjects/PythonErrors/TypeError Can’t Multiply Sequence by non-int of Type ‘float’ In Python.py", line 3, in <module>
    print(2.0 * my_list)
TypeError: can't multiply sequence by non-int of type 'float'

✯ How to Fix – TypeError: Can’t Multiply Sequence by non-int of Type ‘float’ ?

👉 To avoid the occurrence of TypeError: Can’t Multiply Sequence by non-int of Type ‘float’ you must ensure that the user input is a floatingpoint value by typecasting the string input to float.

Let us have a look at the solutions to this error with the help of numerous scenarios.

⮞ Type 1: Convert Temperature Fahrenheit To Celsius

Problem: given temperature in Fahrenheit; how to convert it to Celsius?

Our Code:

Celsius = input("Enter the temperature: ")
print(Celsius, "°C = ", Celsius * 1.8 + 32, "°F")

Output:

Traceback (most recent call last):
  File "D:/PycharmProjects/PythonErrors/TypeError Can’t Multiply Sequence by non-int of Type ‘float’ In Python.py", line 2, in <module>
    print(Celsius, "°C = ", Celsius * 1.8 + 32, "°F")
TypeError: can't multiply sequence by non-int of type 'float'

Solution:

Celsius = float(input("Enter the temperature: "))
print(Celsius, "°C = ", Celsius * 1.8 + 32, "°F")

Output:

Enter the temperature: 37
37.0 °C =  98.60000000000001 °F

Voila! we have successfully resolved our problem. 🤗

⮞ Type 2:  Multiplying Any Sequential Data-Type (string, tuple or lists) And a Floating-Point Value

Python raises TypeError: can't multiply sequence by non-int of type 'float' every time a sequential data is multiplied by a floating-point value.

Example 1:

li = ['a', 'b', 'c']  # list
tup = (100, 200, 300)  # tuple
print(2.0 * li)
print(2.0 * tup)

# DESIRED OUTPUT:
# ['a', 'b', 'c', 'a', 'b', 'c']
# (100, 200, 300,100, 200, 300)

Output:

C:\Users\DELL\AppData\Local\Programs\Python\Python38\python.exe "D:/PycharmProjects/PythonErrors/TypeError Can’t Multiply Sequence by non-int of Type ‘float’ In Python.py"
Traceback (most recent call last):
  File "D:/PycharmProjects/PythonErrors/TypeError Can’t Multiply Sequence by non-int of Type ‘float’ In Python.py", line 3, in <module>
    print(2.0 * li)
TypeError: can't multiply sequence by non-int of type 'float'

Solution: The error can be avoided by type-casting the float value i.e., 2.0 to an integer value i.e. 2.

li = ['a', 'b', 'c']  # list
tup = (100, 200, 300)  # tuple
print(int(2.0) * li)
print(int(2.0) * tup)

Output:

['a', 'b', 'c', 'a', 'b', 'c']
(100, 200, 300, 100, 200, 300)

Example 2: Let us try and calculate the total tax @10% from a given list of prices.

price = [100, 200, 300]
print('Tax = $%.2f' % sum(price) * 0.1)

# DESIRED OUTPUT:
# Tax = $60.00

Output:

Traceback (most recent call last):
  File "D:/PycharmProjects/PythonErrors/TypeError Can’t Multiply Sequence by non-int of Type ‘float’ In Python.py", line 2, in <module>
    print('Tax = $%f' % sum(price) * 0.1)
TypeError: can't multiply sequence by non-int of type 'float'

Solution:

Since you have the % operator in your expression, the call to sum() is tied to the string, and effectively you have:

<string_value> * tax

The solution lies in adding proper parentheses to force the precedence you want as shown below.

price = [100, 200, 300]
print('Tax = $%.2f' % (sum(price) * 0.1))

Output:

Tax = $60.00

Conclusion

I hope you found this article helpful. Please subscribe and stay tuned for more interesting articles in the future. Happy learning! 📚

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