Python - Rounding by quarter-intervals

Question

I'm running into the following issue:

Given various numbers like:

10.38

11.12

5.24

9.76

does an already 'built-in' function exists to round them up to the closest 0.25 step like e.g.:

10.38 --> 10.50

11.12 --> 11.00

5.24 --> 5.25

9.76 --> 9-75 ?

Or can I go ahead and hack together a function that performs the desired task?

Thanks in advance and

with best regards

Dan

Answer 1

This is a general purpose solution which allows rounding to arbitrary resolutions. For your specific case, you just need to provide 0.25 as the resolution but other values are possible, as shown in the test cases.

def roundPartial (value, resolution):
    return round (value / resolution) * resolution

print "Rounding to quarters"
print roundPartial (10.38, 0.25)
print roundPartial (11.12, 0.25)
print roundPartial (5.24, 0.25)
print roundPartial (9.76, 0.25)

print "Rounding to tenths"
print roundPartial (9.74, 0.1)
print roundPartial (9.75, 0.1)
print roundPartial (9.76, 0.1)

print "Rounding to hundreds"
print roundPartial (987654321, 100)

This outputs:

Rounding to quarters
10.5
11.0
5.25
9.75
Rounding to tenths
9.7
9.8
9.8
Rounding to hundreds
987654300.0

Answer 2

>>> def my_round(x):
...  return round(x*4)/4
... 
>>> 
>>> assert my_round(10.38) == 10.50
>>> assert my_round(11.12) == 11.00
>>> assert my_round(5.24) == 5.25
>>> assert my_round(9.76) == 9.75
>>>