什么定义在Python中的浮点精度？ [英] What defines floating point precision in python?

问题描述

我在Erlang学到了完全相同的操作符，比较只有值，而且还有数据的数据类型，我很好奇Python是如何工作的，以及它的唯一等于运算符。因此，在确定

 >>> 1 == 1.0 
 True 
  

我想知道浮点精度，

 >>> 0.9999999999999999 == 1 
 False 
>>> 0.99999999999999999 == 1 
 True 
>>> 
  

有人可以解释浮点精度是如何确定的吗？它在2.7.1和3.1.2中都是一样的。

解决方案

请检查Python文档：

http://docs.python.org/tutorial/floatingpoint .html

I learnt of the "exactly equal to" operator in Erlang, which compares not only values, but also data types of numbers, and I was curious about how things work in Python and its lone "equals to" operator. So after making sure that

>>> 1 == 1.0 
True

I wondered about the floating point precision, and got to this

>>> 0.9999999999999999 == 1
False
>>> 0.99999999999999999 == 1
True
>>>

Could someone explain how floating point precision is determined here? It works the same in both 2.7.1 and 3.1.2

解决方案

Please check with the Python documentation:

http://docs.python.org/tutorial/floatingpoint.html

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