Task: given a list, produce a tally of all the distinct items in

the list (for some suitable notion of "distinct").

Example: if the list is ['a', 'b', 'c', 'a', 'b', 'c', 'a', 'b',

'c', 'a'], then the desired tally would look something like this:

[('a', 4), ('b', 3), ('c', 3)]

I find myself needing this simple operation so often that I wonder:

1. is there a standard name for it?

2. is there already a function to do it somewhere in the Python

standard library?

Granted, as long as the list consists only of items that can be

used as dictionary keys (and Python's equality test for hashkeys

agrees with the desired notion of "distinctness" for the tallying),

then the following does the job passably well:

def tally(c):

t = dict()

for x in c:

t[x] = t.get(x, 0) + 1

return sorted(t.items(), key=lambda x: (-x[1], x[0]))

But, of course, if a standard library solution exists it would be

preferable. Otherwise I either cut-and-paste the above every time

I need it, or I create a module just for it. (I don't like either

of these, though I suppose that the latter is much better than the

former.)

So anyway, I thought I'd ask.

~K