Python|十进制 from_float() 方法

Decimal#from_float() ：from_float()是一个 Decimal 类方法，它将浮点数转换为十进制数。

Syntax: Decimal.from_float()

Parameter: Decimal values

Return: converts converts a float to a decimal number, exactly.

代码 #1：from_float() 方法的示例

# Python Program explaining 
# from_float() method
  
# loading decimal library
from decimal import *
  
  
# Initializing a decimal value
a = Decimal(-1)
  
b = Decimal('0.142857')
  
# printing Decimal values
print ("Decimal value a : ", a)
print ("Decimal value b : ", b)
  
  
# Using Decimal.from_float() method
print ("\n\nDecimal a with from_float() method : ", a.from_float(0.1))
  
print ("Decimal b with from_float() method : ", b.from_float(float('nan')))

输出 ：

Decimal value a :  -1
Decimal value b :  0.142857


Decimal a with from_float() method :  0.1000000000000000055511151231257827021181583404541015625
Decimal b with from_float() method :  NaN

代码 #2：from_float() 方法的示例

# Python Program explaining 
# from_float() method
  
# loading decimal library
from decimal import *
  
  
# Initializing a decimal value
a = Decimal('-3.14')
  
b = Decimal('321e + 5')
  
# printing Decimal values
print ("Decimal value a : ", a)
print ("Decimal value b : ", b)
  
  
# Using Decimal.from_float() method
print ("\n\nDecimal a with from_float() method : ", a.from_float(0.02))
  
print ("Decimal b with from_float() method : ", b.from_float(float('-inf')))

输出 ：

Decimal value a :  -3.14
Decimal value b :  3.21E+7


Decimal a with from_float() method :  0.0200000000000000004163336342344337026588618755340576171875
Decimal b with from_float() method :  -Infinity