How Can I Group Equivalent Items Together In A Python List?

I have a list like x = [2, 2, 1, 1, 1, 1, 1, 1] I would like to put the repeated numbers together like [[2,2],[1,1,1,1,1,1]]

Solution 1:

[list(g) for k, g in itertools.groupby(iterable)]

This is exactly what itertools.groupby is for.

If you want nonconsecutive numbers grouped, like in the comment by @Michal,

[list(g) for k, g in itertools.groupby(sorted(iterable))]