What is the meaning of [...] in python? [duplicate]

Question

Instead of a list with some objects in it, I get [...] whenever I run my code. I'd like to know what it means, in order to debug my code.

Answer 1

That most probably is a reference to the object itself. Example:

In [1]: l = [0, 1]

In [2]: l.append(l)

In [3]: l
Out[3]: [0, 1, [...]]

In the above, the list l contains a reference to itself. This means, you can endlessly print elements within it (imagine [0, 1, [0, 1, [0, 1, [...]]]] and so on) which is restricted using the ... IMO, you are incorrectly appending values somewhere in your code which is causing this.

A more succinct example:

In [1]: l = []

In [2]: l.append(l)

In [3]: l
Out[3]: [[...]]

Answer 2

>>> data = []
>>> data.append([1,3,4])
>>> data
[[1, 3, 4]]
>>> data.append([1,3,data])
>>> data
[[1, 3, 4], [1, 3, [...]]]
>>> data[0]
[1, 3, 4]
>>> data[1]
[1, 3, [[1, 3, 4], [...]]]
>>> data.append([1,2,data])
>>> data
[[1, 3, 4], [1, 3, [...]], [1, 2, [...]]]
>>> data[2]
[1, 2, [[1, 3, 4], [1, 3, [...]], [...]]]

Then it just gets weird