Méthode d'utilisation de float() en Python et exemples

Python built-in functions

The float() method returns a floating-point number from numbers or strings.

The syntax of float() is:

float([x])

float() parameter

float() method takes one parameter:

• x (optional) 　-The number or string that needs to be converted to a floating-point number.
  If it is a string, then the string should contain a decimal point

float() return value

float() method returns:

• Equivalent floating-point number when passing parameters

• If no parameter is passed, it is 0.0

• If the parameter is out of the range of Python float, an OverflowError exception will occur

Example1：How does float() work in Python?

# Parameter is integer
print(float(10))
# Parameter is floating
print(float(11.22))
# Parameter is a string float
print(float("-13.33"))
# Parameter is a string with spaces
print(float("　　　　　-24.45\n"))
# Parameter is a string, will throw a float error
print(float("abc"))

When running the program, the output is:

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

Example2：Is float() used for infinity and Nan (not a number)?

# Parameter is NaN
print(float("nan"))
print(float("NaN"))
# Parameter is inf/infinity
print(float("inf"))
print(float("InF"))
print(float("InFiNiTy"))
print(float("infinity"))

When running the program, the output is:

nan
nan
inf
inf
inf
inf

Python built-in functions