Python: Lazy Counters

python_lazy_counters.py

#!python
# Reference: 1) https://docs.python.org/3/library/collections.html#collections.defaultdict
# Reference: 2) https://www.python.org/dev/peps/pep-0342/

from collections import defaultdict

# Example 1:  Using coroutine via generator for multivalue counter
def multi_counter_generator():
    cnt = defaultdict(int)
    incr = yield cnt.items()
    while True:
        if incr is None:
            for k in cnt.keys():
                cnt[k] += 1
            incr = yield cnt.items()
        else:
            if not isinstance(incr, (list, tuple)):
                cnt[incr] += 1
                incr = yield cnt[incr]
            else:
                for i in incr:
                    cnt[i] += 1
                incr = yield [(i,cnt[i]) for i in incr]


# Example 2:  Using coroutine via generator for counter with dynamic increments
def counter_generator(start=0):
    cnt = start
    incr = yield cnt
    while True:
        if incr is None:
            cnt += 1
        else:
            cnt += incr
        incr = yield cnt


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