Circular Reference With Python Lists

Can someone explain this? >>> x=x[0]=[0] >>> x [[...]] >>> x is x[0] True >>> x[0][0][0][0][0][0][0] [[...]] >>> x in x True what is [

Solution 1:

That's just Python telling you that you have a circular reference; it's smart enough not to enter an infinite loop trying to print it out.

Solution 2:

It's output by the method responsible for generating the representation of the structure. It represents a recursive structure, elided since it can be nested infinitely.

Solution 3:

iPython will do this:

[<Recursion on list with id=38505216>]

It's the same thing; the interpreter telling you that you have a recursive data structure.