Processing alternate element in for loop without using index value [duplicate]

Question

I have list of elements with dictionary, for simplicity I have written them as strings:

ls = ['element1', 'element2', 'element3', 'element4', 'element5', 'element6', 'element7', 'element8', 'element9', 'element10']

I am trying to process pair of element from list as follow:

#m1. Step for loop by size two with if condition 
for x in ls:
    if ls.index(x)%2 == 0:
        # my code to be process
        print(x) # for simplicity I just printed element


#m2. tried another way like below:
for x in range(0, len(ls), 2):
    # this way give me output of alternate element from list
    print(ls[x])

Is there any way to get only alternate elements while iterating the list items in m1 just like m2?

Answer 1

You can slice the list in steps of two; exploiting memory:

for x in ls[::2]:
    print(x)