Python float()

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

The syntax for float() is:

float([x])

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
Different parameters with float()
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).

Return value from float()

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

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'

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

nan
nan
inf
inf
inf
inf