The error message:
TypeError: can't multiply sequence by non-int of type 'float'
occurs when you try to multiply a sequence (like a list or string) by a float instead of an integer.
1. Causes and Solutions
Cause 1: Multiplying a String or List by a Float
Python allows repeating sequences using multiplication, but only by an integer. Multiplying by a float raises an error.
Incorrect Code:
text = "Hello"
print(text * 2.5) # TypeError
numbers = [1, 2, 3]
print(numbers * 1.5) # TypeError
Solution: Use an Integer for Multiplication
print(text * 2) # Output: HelloHello
print(numbers * 3) # Output: [1, 2, 3, 1, 2, 3, 1, 2, 3]
Alternative: Convert Float to Integer
If you want a rounded repeat, convert the float to an integer.
print(text * int(2.5)) # Output: HelloHello
Cause 2: Using a Float in a Loop Repetition (* Operator)
If you’re trying to initialize a list with repeated values but use a float, you’ll get this error.
Incorrect Code:
arr = [0] * 2.5 # TypeError
Solution: Convert the Float to an Integer
arr = [0] * int(2.5) # Works correctly
print(arr) # Output: [0, 0]
Cause 3: Accidentally Using Float in Mathematical Operations with a Sequence
If a float is unintentionally introduced into an expression with a sequence, Python will raise this error.
Incorrect Code:
num_repeats = 4 / 2 # This is a float (2.0)
text = "Hi"
print(text * num_repeats) # TypeError
Solution: Convert to an Integer
num_repeats = int(4 / 2)
print(text * num_repeats) # Output: HiHi