Sum of a list 2 elements by 2 elements

Question

I have a 25 elements list like

tab=[6, 5, 5, 6, 3, 3, 2, 3, 2, 5, 6, 3, 2, 4, 5, 6, 4, 2, 1, 3, 1, 1, 4, 1, 5]

And I want to create a new list tab1 which display the sum of the elements of the list two by two, if the list is odd I don't have to calculate the sum on the last element. And it has to be done with a for loop for... any ideas? Any help would be appreciated. I tried on my side but without success.

i tried this :

for i in tab:
print(sum(i:len(tab))

it gives me a syntax error and i tried some of others things but didn't work...

i tried this too

for i in tab:
print(sum(i,i+1))

didn't work too

and when i do this

sum=0
for i in tab:
print(sum(tab[i]+tab[i+1]))

it gives me back : TypeError: 'int' object is not callable

Answer 1

You could iterate over the list with steps of 2.

orig_len = len(tab)  # List length
tab1 = []
for i in range(0, orig_len - orig_len%2, 2):
  tab1.append(tab[i] + tab[i+1])
print(tab1)

You have to round down the number to first smaller even number, which is that orig_len - orig_len%2 does.