joe_schmoe wrote:
Greetings
I am attempting to compare the items in two lists across two criteria -
membership and position. For example:
list_a = [ 0, 4, 3, 6, 8 ]
list_b = [ 1, 8, 4, 6, 2 ]
Membership = There are 3 items that are common to both lists, that is 3
items in list_a have membership in list_b (viz: 4, 6, 8);
Use sets:
>>> list_a = [ 0, 4, 3, 6, 8 ]
>>> list_b = [ 1, 8, 4, 6, 2 ]
>>> set(list_a).intersection(list_b)
set([8, 4, 6])
Position = There is 1 item in list_a that is also in the same position
in both lists (viz: 6).
Use zip() to iterate two lists in parallel and a list comprehension to
accumulate the results:
>>> [ a for a, b in zip(list_a, list_b) if a==b ]
[6]
or if you want the position of the item use enumerate() to get the index:
>>> [ i for i, (a, b) in enumerate(zip(list_a, list_b)) if a==b ]
[3]
Kent
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