Python-哪种初始化列表更快？
Python是一种非常灵活的语言，可以通过多种方式执行单个任务，例如，可以通过多种方式执行初始化列表。但是，这些看似相似的方法之间存在细微的差异。与C++或Java相比，因其简单性和可读性而广受欢迎的Python同样因其速度慢而臭名昭著。众所周知，“for”循环速度较慢，而诸如map()和filter()之类的方法由于采用C语言编写，因此速度较快。
示例
# import time module to calculate times
import time
# initialise lists to save the times
forLoopTime = []
whileLoopTime = []
listComprehensionTime = []
starOperatorTime = []
# repeat the process for 500 times
# and calculate average of times taken.
for k in range(500):
# start time
start = time.time()
# declare empty list
a = []
# run a for loop for 10000 times
for i in range(10000):
a.append(0)
# stop time
stop = time.time()
forLoopTime.append(stop-start)
# start time
start = time.time()
# declare an empty list
a = []
i = 0
# run a for loop 10000 times
while(i<10000):
a.append(0)
i+= 1
stop = time.time()
whileLoopTime.append(stop-start)
start = time.time()
# list comprehension to initialize list
a = [0 for i in range(10000)]
stop = time.time()
listComprehensionTime.append(stop-start)
start = time.time()
# using the * operator
a = [0]*10000
stop = time.time()
starOperatorTime.append(stop-start)
print("Average time taken by for loop: " + str(sum(forLoopTime)/100))
print("Average time taken by while loop: " + str(sum(whileLoopTime)/100))
print("Average time taken by list comprehensions: " + str(sum(listComprehensionTime)/100))
print("Average time taken by * operator: " + str(sum(starOperatorTime)/100))输出结果
Average time taken by for loop: 0.00623725175858 Average time taken by while loop: 0.00887670278549 Average time taken by list comprehensions: 0.00318484544754 Average time taken by * operator: 0.000371544361115