>>> float(str(0.65000000000000002))
0.65000000000000002
>>> float(str(0.47000000000000003))
0.46999999999999997 ???
这里发生了什么?如何将 0.47000000000000003
转换为字符串并将结果值转换回浮点数?
What is going on here?
How do I convert 0.47000000000000003
to string and the resultant value back to float?
我在 Windows 上使用 Python 2.5.4.
I am using Python 2.5.4 on Windows.
str(0.47000000000000003)
给 '0.47'
和 float('0.47')
可以是 0.46999999999999997
.这是由于浮点数的表示方式(参见这篇 wikipedia 文章)
str(0.47000000000000003)
give '0.47'
and float('0.47')
can be 0.46999999999999997
.
This is due to the way floating point number are represented (see this wikipedia article)
注意:float(repr(0.47000000000000003))
或 eval(repr(0.47000000000000003))
会给你预期的结果,但你应该使用 十进制,如果你需要精确的话.
Note: float(repr(0.47000000000000003))
or eval(repr(0.47000000000000003))
will give you the expected result, but you should use Decimal if you need precision.
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