How to check if an object is a list or tuple (but not string)?

Question

This is what I normally do in order to ascertain that the input is a `list`/`tuple` - but not a `str`. Because many times I stumbled upon bugs where a function passes a `str` object by mistake, and the target function does `for x in lst` assuming that `lst` is actually a `list` or `tuple`. ``` assert isinstance(lst, (list, tuple)) ``` My question is: is there a better way of achieving this?

Accepted Answer

In python 2 only (not python 3):

```
assert not isinstance(lst, basestring)
```

Is actually what you want, otherwise you'll miss out on a lot of things which act like lists, but aren't subclasses of `list` or `tuple`.

How to check if an object is a list or tuple (but not string)?

Solution

Problem