Question

I have two lists.

One list contains only codes e.g.:

b3b
3cd
6f6
4d8
96b
00a
774
eb3
607
7e5

The other list contains code with names e.g.

b3b:John
607:Eric
7e5:Jarrold

But the list is not compleet yet.

What I want as output, because the other cannot be removed and has to be in the right order, e.g.

b3b:John
3cd
6f6
4d8
96b
00a
774
eb3
607:Eric
7e5:Jarrold

Already have this code but it only returns True or False but that’s not what I want.

list1 = [line.strip() for line in open('list1')]
list2 = [line.strip() for line in open('list2')]

comp = [i[:3] for i in list2]

for i in list1:
    print(i, i in list2)

Maybe anyone who can help me with this?

Answer 1

You should use a dictionary mapping keys to names instead of a list as the second data structure:

with open("list1") as f:
    keys = [line.strip() for line in f]
with open("list2") as f:
    names = dict(line.strip().split(":", 1) for line in f)

Now you can efficiently implement your loop:

for k in keys:
    print(k, names.get(k, ""))

Performing a linear search in list2 for every entry of list1 would be rather inefficient. Apart from the better performance, a dictionary is also a better model of the meaning of your data.