Check if list contains another list in python

Question

I have two lists, one containing lists of album, file pairs and the other containing only info about one photo - album (at position 0) and file (a

Answer 1

photos = [["Trip to Thailand", "IMG_001.jpg"], ["Latvia 2010", "IMG_001.jpg"]]
photo = ["Latvia 2010", "IMG_001.jpg"]
print (photo in photos)
True

There is no difference, you would check exactly as you would for a string.

Answer 2

Similarly like photo in photos for strings. Not just similarly, exactly like that. photo in photos works for lists inside lists too:

>>> photos = [["Trip to Thailand", "IMG_001.jpg"], ["Latvia 2010", "IMG_001.jpg"]]
>>> photo = ["Latvia 2010", "IMG_001.jpg"]
>>> photo in photos
True

Membership testing against a list simply iterates over the list and uses == equality testing with each element to see if there is a match. Your photo list tests as equal to the second element:

>>> photos[1] == photo
True

because all strings in both lists are equal.