(Maybe b/c I'm from a C++ world) I want to verify some python variable is
list(string) or list(dict(int, string)) or SomethingIterable(string)
Is there a simple and unified way to do it? (Instead of writing customized code to iterate and verify each instance..)
I emphasize that I understand in Python list can have elements of different types, which is exactly the reason why I ask how to verify a list which are composed by just a certain type e.g. string.
In Python lists can be composed of mixed types, there is no way to do something like setting the "type" of a list. Also, even if you could, this "type" is not enforced and could change at any time.
["Hi", 0, count()] is a valid list in python.
lists should typically be of homogeneous type. But yeah, it's completely unenforced/unenforceable; we're all adults, and if you want to do terrible things with lists, that's between you, your conscience, and the pitchfork wielding mobs of programmers who have to read/maintain your code later. tuple is either homogeneous (if being used logically as an immutable list), or heterogeneous (when being used logically as a "lightweight object"; e.g. any case where collections.namedtuple might be appropriate).It seems that you are looking for an array (array.array), not a list:
>>> l = [1]
>>> l.append('a')
>>> import array
>>> a = array.array('l')
>>> a.append(3)
>>> a.append('a')
Traceback (most recent call last):
File "<stdin>", line 1, in <module>
TypeError: an integer is required (got type str)
>>> a
array('l', [3])
As you get more and more comfortable with Python, though, you will gradually learn how to structure your code in such a way that type-checking becomes unnecessary. Personally, I've never had to use an array.array in Python (except in cases like this, where I'm specifically working with that module).
isinstance?hasattr(var, "__iter__")?