Python 保留小数后精度问题

[mili8908]

a = 0.9987623
# 将 a 保留两位小数得到
a = 0.99

[zh0408]

round()

[gnozix]

format

[mili8908]

@zh0408
In [2]: a = 0.998765

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

[gimp]

>>> 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]

int(a*100)/100

[lxy42]

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]

@gimp 这就厉害了

[pyse]

你们的为什么没有四舍五入呢？？？


>>> a = 0.9987623

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

1.00