Compare 2 elements in single list

Question

I'm looking for a way to compare 2 elements in single list of python. For example if i have numbers = [1,3,5,7,9] i want to compare 1 with 3 and so on till the list ends.

Any suggestions?

Answer 1

for i,j in zip(numbers[:-1],numbers[1:]):
    compare(i,j)

This compares all adjacent elements, by lining up the list excluding the last element, and the list excluding the first element.

Answer 2

Try using itertools :

>>> from itertools import combinations
>>> for element in combinations(numbers, 2):
...     print element
...
(1,3)
(1,5)
(1,7)
(1,9)
(3,5)
(3,7)
(3,9)
(5,7)
(5,9)
(7,9)

Answer 3

For example:

def compare(x, y):
    """
    here you can put your code, using 'x' and 'y' var
    """
    if (x + y) % 2 == 0:
        return x

l = [1,3,5,7,9]
l2 = reduce(compare, l)
print l2

I hope help you ;-)