如何将浮点小数固定为两位，即使数字为2.00000

Question

This is what I have:
x = 2.00001

This is what I need:
x = 2.00

I am using:
float("%.2f" % x)

But all I get is:
2

How can I limit the decimal places to two AND make sure there are always two decimal places even if they are zero?
Note: I do not want the final output to be a string.

Answer 1

This works:

'%.2f" % float(x)

Previously I answered with this:

How about this?

def fmt2decimals(x):
  s = str(int(x*100))
  return s[0:-2] + '.' + s[-2:]

AFAIK you can't get trailing zeros with a format specification like %.2f .

Answer 2

If you can use decimal ( https://docs.python.org/2/library/decimal.html ) instead of float:

from decimal import Decimal
Decimal('7').quantize(Decimal('.01'))

quantize() specifies where to round to.

https://docs.python.org/2/library/decimal.html#decimal.Decimal.quantize

Answer 3

Have you taken a look at the decimal module? It allows you to do arithmetic while maintaining the proper precision:

>>> from decimal import Decimal
>>> a = Decimal("2.00")
>>> a * 5
Decimal('10.00')
>>> b = Decimal("0.05")
>>> a * b
Decimal('0.1000')

Answer 4

Python还具有内置的“舍入”功能： x = round(2.00001, 2)我相信这是您将使用的命令。

Answer 5

Well, in Python, you can't really round to two zeroes without the result being a string. Python will usually always round to the first zero because of how floating point integers are stored. You can round to two digits if the second digit is not zero, though.

For example, this:

round(2.00001, 2)
#Output: 2.0

vs this:

round(2.00601, 2)
#Output: 2.01