✯ 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 - 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 floating–point 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 = $60.00Output:
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 %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
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