Limiting floats to two decimal points

Question

I want a to be rounded to 13.95.

>>> a
13.949999999999999
>>> round(a, 2)
13.949999999999999

The ro

Answer 1

Nobody here seems to have mentioned it yet, so let me give an example in Python 3.6's f-string/template-string format, which I think is beautifully neat:

>>> f'{a:.2f}'

It works well with longer examples too, with operators and not needing parens:

>>> print(f'Completed in {time.time() - start:.2f}s')

Answer 2

To round a number to a resolution, the best way is the following one, which can work with any resolution (0.01 for two decimals or even other steps):

>>> import numpy as np
>>> value = 13.949999999999999
>>> resolution = 0.01
>>> newValue = int(np.round(value/resolution))*resolution
>>> print newValue
13.95

>>> resolution = 0.5
>>> newValue = int(np.round(value/resolution))*resolution
>>> print newValue
14.0

Answer 3

What about a lambda function like this:

arred = lambda x,n : x*(10**n)//1/(10**n)

This way you could just do:

arred(3.141591657,2)

and get

3.14

Answer 4

lambda x,n:int(x*10n+.5)/10n has worked for me for many years in many languages.

Answer 5

I feel that the simplest approach is to use the format() function.

For example:

a = 13.949999999999999
format(a, '.2f')

13.95

This produces a float number as a string rounded to two decimal points.

Answer 6

orig_float = 232569 / 16000.0

14.5355625

short_float = float("{:.2f}".format(orig_float)) 

14.54