class Histogram:
# "catSeq" represent a particular sequence of category identifier.
def __init__(self, catSeq):
# Histogram.frequenceCounts , is actually a hash table
self._frequenceCounts = HashMap()
for L_category in catSeq:
# so it has a addkey() method, here "category" is single character-based key, "0" is value
# the letter-based key with uppercase will be hash to integer-based key
# and a empty slot will be fill with new entry, that is,
# key-value(0) pair
# the value(0) represent the initialized counter=0 for each category
self._frequenceCounts.addkey(L_category, 0)
def getCount(self, category):
# determine if key in hash table
assert category in self._frequenceCounts, "Invalid histogram category !"
return self._frequenceCounts._readValue(category)
def increaseCount(self, category):
# determine if key in hash table
assert category in self._frequenceCounts, "Invalid histogram category !"
value = self._frequenceCounts._readValue(category)
# in the main() function of buildHistogram.py,
# each time we achieve a data belongs to particular category,
# add corresponding counter value by one
self._frequenceCounts.addkey(category, value + 1)
def totalCount(self):
total = 0
for L_category in self._frequenceCounts:
total += self._frequenceCounts._readValue(category)
return total
# returns an iterator for traversing the categories.
def __iter__(self):
return iter(self._frequenceCounts)