python - Pop multiple items from the beginning and end of a list

Question

Suppose I have a list of items like this:

mylist=['a','b','c','d','e','f','g','h','i']

I want to pop two items from the left (i.e. a and b) and two items from the right (i.e. h,i). I want the most concise an clean way to do this. I could do it this way myself:

for x in range(2):
    mylist.pop()
    mylist.pop(0)

Any other alternatives?

question from:https://stackoverflow.com/questions/24245057/pop-multiple-items-from-the-beginning-and-end-of-a-list

Answer 1

From a performance point of view:

• mylist = mylist[2:-2] and del mylist[:2];del mylist[-2:] are equivalent
• they are around 3 times faster than the first solution for _ in range(2): mylist.pop(0); mylist.pop()

Code

iterations = 1000000
print timeit.timeit('''mylist=range(9)
for _ in range(2): mylist.pop(0); mylist.pop()''', number=iterations)/iterations
print timeit.timeit('''mylist=range(9)
mylist = mylist[2:-2]''', number=iterations)/iterations
print timeit.timeit('''mylist=range(9)
del mylist[:2];del mylist[-2:]''', number=iterations)/iterations

output

1.07710313797e-06

3.44465017319e-07

3.49956989288e-07