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 floating number
Integer Use as 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()

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

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"))

When you run the program, the output will be:

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"))

When you run the program, the output will be:

nan
nan
inf
inf
inf
inf