[Python-announce] rounder: A Python package for rounding numbers in complex objects

[Marcin Kozak]

Hi all!

When you work with numbers and need to print them, more often than not you
want to round them. You can use the built-in round() function:
>>> round(1.123, 2)
1.12
>>> x = [1.123, 44.32, 12.11234]
>>> [round(x_i, 2) for x_i in x]
[ 1.12, 44.32, 12.11]

However, when you want to round numbers in a more complex Python object,
you need to be careful; you may also need to write a dedicated function to
round numbers in this object, and you may need to update it if the object's
structure changes.

Now, you do not need to do that: use the rounder Python package instead. It
will round numbers in any non-nested or nested Python object, using the
following functions:
* round_object(obj, digits), which rounds numbers in the object to a
provided number of decimal digits
* ceil_object(obj), which rounds numbers up to the nearest integer
* floor_object(obj), which rounds numbers down to the nearest integer
* signif_object(obj, digits), which rounds numbers to a number of
significant digits

So, for example:

>>> obj = {'float': 1.345442, 'list': [1.1222, 1.1226, "string"], 'set':
{1.1222, 1.1226}, 'tuple': (1.1222, 1.1226)}
>>> round_object(obj, 2)
{'float': 1.35, 'list': [1.12, 1.12, "string"], 'set': {1.12}, 'tuple':
(1.12, 1.12)}
>>> signif_object(obj, 3)
{'float': 1.35, 'list': [1.12, 1.12, "string"], 'set': {1.12}, 'tuple':
(1.12, 1.12)}

The package offers also two other functions:
* signif(x, digits), to round a number to significant digits
* map_object(map_function, obj, use_copy=False)

The latter function is a generalized function that applies callable
map_function to all numbers in obj. Consider this simplistic example:
>>> map_object(lambda x: x**2, {'a': 3, 'b': [1, 2, 3]})
{'a': 9, 'b': [1, 4, 9]}

The package works with objects of many different types, not only those
shown above. It works under both Windows and Linux. You can install it from
PyPi:
$ pip install rounder

You will learn more about it from its GitHub repo:
https://github.com/nyggus/rounder.

Happy rounding!

Pozdrawiam,
Marcin