On Mon, Dec 18, 2017 at 6:51 PM, Joel Croteau <jcroteau@gmail.com> wrote:
It would be useful in many scenarios for values in collections.Counter to be allowed to be floating point. I know that Counter nominally emulates a multiset, which would suggest only integer values, but in a more general sense, it could be an accumulator of either floating point or integer data. As near as I can tell, Collection already does support float values in both Python 2.7 and 3.6, and the way the code is implemented, this change should be a no-op. All that is required is to update the documentation to say floating-point values are allowed, as it currently says only integers are allowed.
That's beyond the scope of Counter. I think what you really want is a generalization of Counter which represents a key'd number bag. A dict of key=>number which supports arithmetic operations, like Numpy arrays are to lists. Example methods: __init__(...): Like dict's version, but it will combine the values of duplicate keys in its params. update(...): Similar to __init__. fromkeys(...): Like dict's version, but uses 0 or 1 as the default value, and combines values like the constructor. With value=1, this is roughly equivalent to the Counter constructor. <arithmetic operators>: Arithmetic with other number bags, with dicts, and with number-like values. clearsmall(tolerance=0): Removes keys whose values are close to 0. Other methods may take inspiration from Numpy. The class should probably be a third-party package (and probably already is), so that the method list can be solidified first.