Python 保留小数后精度问题

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这是一个创建于 2067 天前的主题，其中的信息可能已经有所发展或是发生改变。

a = 0.9987623
# 将 a 保留两位小数得到
a = 0.99

Python

小数

保留

精度

8 条回复 • 2018-08-23 13:43:59 +08:00

zh0408

2018-08-22 17:09:14 +08:00

round()

gnozix

2018-08-22 17:14:39 +08:00

format

mili8908

2018-08-22 17:21:28 +08:00

@zh0408
In [2]: a = 0.998765

In [3]: round(a,2)
Out[3]: 1.0

gimp

2018-08-22 17:26:01 +08:00

>>> r = lambda f: f - f % 0.01
>>> r(2.368)
2.36
>>> r(2.36888888)
2.36
>>> r(2.323)
2.32
>>> r(2.326)
2.32

摘自： https://www.reddit.com/r/learnpython/comments/4nj5gu/how_to_get_float_to_two_decimal_places_without/

chenxingyu1021

2018-08-22 17:38:15 +08:00

int(a*100)/100

lxy42

2018-08-22 17:39:50 +08:00

Q. In a fixed-point application with two decimal places, some inputs have many places and need to be rounded. Others are not supposed to have excess digits and need to be validated. What methods should be used?

A. The quantize() method rounds to a fixed number of decimal places. If the Inexact trap is set, it is also useful for validation:

>>>
>>> TWOPLACES = Decimal(10) ** -2 # same as Decimal('0.01')
>>>
>>> # Round to two places
>>> Decimal('3.214').quantize(TWOPLACES)
Decimal('3.21')

mili8908

2018-08-23 09:16:58 +08:00

@gimp 这就厉害了

pyse

2018-08-23 13:43:59 +08:00

你们的为什么没有四舍五入呢？？？

>>> a = 0.9987623

>>> print("%.2f" %a)

1.00