def test_reduce_sum_keys(self):
"""
simple test to reduce a dictionary to the sum of its keys
"""
dictionary = {
1: { 2: {}, 3: {} },
2: { 4: {}, 6: {} },
}
# filter out the odd elements
actual = dicttools.reduce(lambda acc, key, _: acc + key, dictionary, 0)
self.assertEquals(18, actual, msg="%s != %s" % (actual, 18))
def test_reduce_performance(self):
total = 3000000
items = [ (x, float(x)) for x in range(0, total) ]
dictionary = dict(items)
start = time.time()
dicttools.reduce(lambda acc, x, y: acc + x, dictionary, initializer=0)
dictionary_elapsed = time.time() - start
start = time.time()
reduce(lambda acc, (x,y): acc + x, items, 0)
list_elapsed = time.time() - start
print('\n dict reduce is %2.2fx slower than list reduce' % \
(dictionary_elapsed/list_elapsed))
start = time.time()
dicttools.reduce(lambda acc, x, y: acc + x,
dictionary,
initializer=0,
recursive = False)
dictionary_elapsed = time.time() - start
print(' dict reduce(recursive=False) is %2.2fx slower than list reduce' % \
(dictionary_elapsed/list_elapsed))
def test_reduce_calculate_debt(self):
"""
reduce a dictionary of user transactions to the amount owed by all
users
"""
dictionary = {
'user1': { 'transactions' : [ -100, 50, 25 ] },
'user2': { 'transactions' : [ -200, 200, -100 ] },
}
def calculate_debt(acc, key, value):
"""
calculate from the various transactions the current debt of all
users
"""
if key == 'transactions':
for amount in value:
acc += amount
return acc
# filter out the odd elements
actual = dicttools.reduce(calculate_debt, dictionary, 0)
self.assertEquals(-125, actual, msg="%s != %s" % (actual, -125))
