Strip list to compare with another list

Question

I try to import a list in python. However, I would like to customize my code in such a way, that the list will look like this:

['a', 'b', 'c']

instead of like this:

[["['a','b','c']"]]

The reason is that I have to compare if a list is in another list and it won't succeed when the list is not formatted well. The rest of the code looks like this:

def check(a1, a2):
    listA = []
    listB = []
    listA.append(a1)
    listB.append(a2)
    if listA in listB:
        print True
    else:
        print False

What do you mean by "formatted well" and how do strings and printing come into play here? — Andreas Grivas, Sep 10 '17 at 20:48
Well, I would like that when I append a1 to listA, the list will be stripped (or something in a way like that) so that when I print listA, it looks like how I mentioned it above. So that I can compare the list with another list. — Max, Sep 10 '17 at 20:48

score 2 · Answer 1 · answered Sep 10 '17 at 20:51

2

I'm not sure if I understand you correctly. Are you looking for this?

a = ['some', 'list', 'items']
print ', '.join(a)

This will print

some, list, items

But that probably won't solve what you're trying to do. Comparing two lists shouldn't involve print at all.

answered Sep 10 '17 at 20:51

Pascal

448
3
11

you're right, it's bad to convert list as string just to be able to use `in` in the string. So it kind of answers. – Jean-François Fabre Sep 10 '17 at 20:55
No I was not very clear in my question. I changed the question now. I want my list like this: ['a', 'b', 'c'] instead of like [["['a','b','c']"]]. Now, it looks like the last example, because I got that data from an .txt file. Do you understand what I mean? – Max Sep 10 '17 at 20:58
I'm still not entirely sure. So you have a string like `"['a', 'b', 'c']"` and you would like to turn that into the python list ['a', 'b', 'c'] ? Is that right? – Pascal Sep 10 '17 at 21:05
Yes that is right! – Max Sep 10 '17 at 21:37
1

Then use my answer and just take away the joining part – whackamadoodle3000 Sep 11 '17 at 23:31

whackamadoodle3000 · Answer 2 · 2017-09-11T23:32:51.930

0

import ast
weirdlist=[["['a','b','c']"]]
print(", ".join(ast.literal_eval(weirdlist[0][0])))

Try this. Formats it like this: a, b, c

EDIT: It seems like the question-asker wanted a list, not a string:

import ast
weirdlist=[["['a','b','c']"]]
print(ast.literal_eval(weirdlist[0][0]))

edited Sep 11 '17 at 23:32

answered Sep 10 '17 at 20:50

whackamadoodle3000

6,684
4
27
44

4

Just use `ast.literal_eval`... – MSeifert Sep 10 '17 at 20:51
I made the edit – whackamadoodle3000 Sep 10 '17 at 20:53

Strip list to compare with another list

2 Answers2