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Test performance of different counting functions in Python
"""
Test performance of these counting methods:
- count_if_else: Set to 1 if not yet seen and increment otherwise
- count_if: Set to 0 if not yet seen, then increment regardless of containment
- count_exception: Attempt to increment and set to 1 if KeyError caught
- count_setdefault: Set default value to 0, then increment
- count_fromkeys: Create dict with necessary keys set to 0, then increment each
- count_set_and_comprehension: Create dict of items and counts using a set
- count_defaultdict: Increment count, automatically setting unseen values to 0
- count_counter: Use counter to count number of occurrences of each value
Results::
$ python3.5 time_count_functions.py 10
List of 5000 random numbers generated in range 0 to 10
count_if_else with time: 1.265662200999941
count_if with time: 1.2668585689998508
count_exception with time: 1.0739088390000688
count_setdefault with time: 2.214042850000169
count_fromkeys with time: 1.1851309869998659
count_defaultdict with time: 0.9649407060001067
count_counter with time: 0.5262270969997189
$ python3.5 time_count_functions.py 250
List of 5000 random numbers generated in range 0 to 250
count_if_else with time: 1.1669907420000527
count_if with time: 1.2063700009998684
count_exception with time: 1.1212147190003634
count_setdefault with time: 2.0994550949999393
count_fromkeys with time: 1.0786272370000916
count_defaultdict with time: 0.9669231920001948
count_counter with time: 0.4641083870001239
$ python3.5 time_count_functions.py 1000
List of 5000 random numbers generated in range 0 to 1000
count_if_else with time: 1.600467853000282
count_if with time: 1.759542166999836
count_exception with time: 1.9168700440000066
count_setdefault with time: 2.639634401999956
count_fromkeys with time: 1.673645010999735
count_defaultdict with time: 1.639715238000008
count_counter with time: 0.7596302269998887
$ python3.5 time_count_functions.py 10000
List of 5000 random numbers generated in range 0 to 10000
count_if_else with time: 1.5599526559999504
count_if with time: 2.221235025999704
count_exception with time: 3.762508314000115
count_setdefault with time: 2.9236523790004867
count_fromkeys with time: 1.9307061319996137
count_defaultdict with time: 3.098360151999259
count_counter with time: 1.0297769050002898
"""
import sys
import timeit
list_size = 5000
range_size = int(sys.argv[1])
setup = """
from collections import defaultdict, Counter
import random
random.seed('MY SEED!')
range_size = """ + str(range_size) + """
list_size = """ + str(list_size) + """
initial_list = [random.randint(0, range_size) for i in range(list_size)]
def count_if_else(my_list):
counts = {}
for item in my_list:
if item not in counts:
counts[item] = 1
else:
counts[item] += 1
return counts
def count_if(my_list):
counts = {}
for item in my_list:
if item not in counts:
counts[item] = 0
counts[item] += 1
return counts
def count_exception(my_list):
counts = {}
for item in my_list:
try:
counts[item] += 1
except KeyError:
counts[item] = 1
return counts
def count_setdefault(my_list):
counts = {}
for item in my_list:
counts.setdefault(item, 0)
counts[item] += 1
return counts
def count_fromkeys(my_list):
counts = dict.fromkeys(my_list, 0)
for item in my_list:
counts[item] += 1
return counts
def count_set_and_comprehension(my_list):
return dict((item, my_list.count(item)) for item in set(my_list))
def count_defaultdict(my_list):
counts = defaultdict(int)
for item in my_list:
counts[item] += 1
return counts
def count_counter(my_list):
return Counter(my_list)
"""
def time_function(func_name):
timed_code = 'new_list = initial_list[:]; {}(new_list)'.format(func_name)
time = min(timeit.Timer(timed_code, setup=setup).repeat(7, 1000))
print("{} with time: {}".format(func_name, time))
print("List of {} random numbers generated in range 0 to {}"
.format(list_size, range_size))
time_function("count_if_else")
time_function("count_if")
time_function("count_exception")
time_function("count_setdefault")
time_function("count_fromkeys")
time_function("count_defaultdict")
time_function("count_counter")
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