Python 设置和计算与列表计算

Question

In python, I wonder something.(Apologize my english) I wonder intersection speed between set and list

There is set A, set B and list C, list D. set A and list C, there is elements like 'lion' 'tiger' 'cat'. set B and list D, there is elements like 'lion' 'monkey' 'cat'.

I want to know intersection speed(A & B, C & D)(result: lion cat). operation A & B is faster than double for loop C and D???

Answer 1

Here is a way to compare several code snippets on time performance. Note that the actual execution times are system dependent, but the ratio of the performances should be approximately equal on different machines.

import timeit

setup = '''\
A = {'dog', 'cat', 'horse'}
B = {'monkey', 'horse', 'dog'}
'''

statement = '''\
intersection = A & B
'''

timeit.timeit(stmt=statement, setup=setup, number=100000)
# 0.0126 sec

setup2 = '''\
C = ['dog', 'cat', 'horse']
D = ['monkey', 'horse', 'dog']
'''

statement2 = '''\
intersection = C[:]
for i in D:
    if i not in intersection:
        intersection.append(i)
'''

timeit.timeit(stmt=statement2, setup=setup2, number=100000)
# 0.0312 sec