round() 似乎没有正确舍入

2022-01-09 00:00:00 python floating-point rounding

问题描述

round() 函数的文档说明您通过它是一个数字,小数点后的位置要四舍五入.因此它应该这样做:

The documentation for the round() function states that you pass it a number, and the positions past the decimal to round. Thus it should do this:

n = 5.59
round(n, 1) # 5.6

但是,实际上,旧的浮点怪异现象逐渐出现,您会得到:

But, in actuality, good old floating point weirdness creeps in and you get:

5.5999999999999996

出于 UI 的目的,我需要显示 5.6.我在互联网上一探究竟,发现了一些 文档取决于我对 Python 的实现.不幸的是,这发生在我的 Windows 开发机器和我尝试过的每台 Linux 服务器上.另见此处.

For the purposes of UI, I need to display 5.6. I poked around the Internet and found some documentation that this is dependent on my implementation of Python. Unfortunately, this occurs on both my Windows dev machine and each Linux server I've tried. See here also.

没有创建自己的圆形库,有什么办法解决这个问题吗?

Short of creating my own round library, is there any way around this?


解决方案

我无法控制它的存储方式,但至少格式可以正常工作:

I can't help the way it's stored, but at least formatting works correctly:

'%.1f' % round(n, 1) # Gives you '5.6'

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