Python 保留小数后精度问题

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This topic created in 2958 days ago, the information mentioned may be changed or developed.

a = 0.9987623
# 将 a 保留两位小数得到
a = 0.99

Python

小数

保留

精度

8 replies • 2018-08-23 13:43:59 +08:00

zh0408

Aug 22, 2018

round()

gnozix

Aug 22, 2018

format

mili8908

Aug 22, 2018

@zh0408
In [2]: a = 0.998765

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

gimp

Aug 22, 2018

>>> 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

Aug 22, 2018

int(a*100)/100

lxy42

Aug 22, 2018

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

Aug 23, 2018

@gimp 这就厉害了

pyse

Aug 23, 2018

你们的为什么没有四舍五入呢？？？

>>> a = 0.9987623

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

1.00