Python 102

counting.py

###
# how many times have you done something like this?
###

# check if dict has key
# if so then increment value
# if not then add key and init value to 1

def increment(d, v):
    if v in d:
        d[v] += 1
    else:
        d[v] = 1

# test
test_dict = {}
increment(test_dict, "apple")
increment(test_dict, "apple")
increment(test_dict, "apple")
increment(test_dict, "pear")

print test_dict
# > {'pear': 1, 'apple': 3} 

###
# instead of that, with Python, juse use Counter
###

# test with Counter object
from collections import Counter
c = Counter()
c["apple"] += 1
c["apple"] += 1
c["apple"] += 1
c["pear"] += 1

print c
print dict(c)
# > Counter({'apple': 3, 'pear': 1})
# > {'pear': 1, 'apple': 3}