PythonBuilt-in functions
float()
Converts a value to a floating-point number.
- Returns
- A floating-point number.
Example
#Python
print(float("3.5"))
print(float(7))
print(float("3,5".replace(",", ".")))
print(0.1 + 0.2)
print(round(0.1 + 0.2, 2))Resultsaved result, you can check it
3.5
7.0
3.5
0.30000000000000004
0.3
Definition and usage
#The float() function creates a floating-point number from a string or an integer. The decimal separator must be a dot, so a string like "3,5" raises an error and has to be converted to "3.5" first.
Floating-point numbers have limited precision, which is why 0.1 + 0.2 gives 0.30000000000000004. That's not a bug in Python, just how computers store decimal fractions.
Special values are created from strings: float("inf") is infinity, and float("nan") is "not a number". For financial calculations, the decimal module is a better choice.
Syntax
#Syntax
float(x)Parameters
#x
a string or number
The value to convert.
Good practices
#- Don't compare floating-point numbers with
==. Usemath.isclose(a, b). - Store money amounts in cents as an
int, or use theDecimaltype.
Related entries
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