Python float() - VietMX's Blog

Table of Contents

1. float() Syntax
2. float() Parameters
3. float() Return Value
4. Example 1: How float() works in Python?
5. Example 2: float() for infinity and Nan(Not a number)?

In this tutorial, we will learn about the Python float() method with the help of examples.

The float() method returns a floating point number from a number or a string.

Example

int_number = 25

# convert int to float
float_number = float(int_number)
print(float_number)

# Output: 25.0

1. float() Syntax

The syntax for float() is:

float([x])

2. float() Parameters

The float() method takes a single parameter:

x (Optional) – number or string that needs to be converted to floating point number
If it’s a string, the string should contain decimal points

Parameter Type	Usage
Float number	Use as a floating number
Integer	Use as an integer
String	Must contain decimal numbers. Leading and trailing whitespaces are removed. Optional use of “+”, “-” signs. Could contain `NaN`, `Infinity`, `inf` (lowercase or uppercase).

3. float() Return Value

The float() method returns:

Equivalent floating point number if an argument is passed
0.0 if no arguments passed
OverflowError exception if the argument is outside the range of Python float

4. Example 1: How float() works in Python?

# for integers
print(float(10))

# for floats
print(float(11.22))

# for string floats
print(float("-13.33"))

# for string floats with whitespaces
print(float("     -24.45\n"))

# string float error
print(float("abc"))

Output

10.0
11.22
-13.33
-24.45
ValueError: could not convert string to float: 'abc'

5. Example 2: float() for infinity and Nan(Not a number)?

# for NaN
print(float("nan"))
print(float("NaN"))

# for inf/infinity
print(float("inf"))
print(float("InF"))
print(float("InFiNiTy"))
print(float("infinity"))

Output