How to count the number of instances of a class within a list?

Question

I have a list that I am appending different objects to.

How would I find the total number of instances of a specific class within that list please?

We can't help you if you don't provide the code/variables you have trouble with. — Nuageux, May 15 '17 at 12:56

Trolldejo · Accepted Answer · 2017-05-17T07:29:28.053

1

print(sum([1 for x in llist if isinstance(x, my_class)]))

edited May 17 '17 at 07:29

answered May 15 '17 at 12:57

Trolldejo

2

you need double equal signs to check equality `==`. And I would go with `isinstance()` like `isinstance(x, my_class)` – Ma0 May 15 '17 at 12:58
could you justify how isinstance(x, my_class) might be a better option than the usage of type() == ? – Trolldejo May 15 '17 at 16:06
This is a fair question.. I have only used (and saw used) `type` only to check against *variable types* (which are also classes) but never to check for custom classes (user-defined ones). So it is more a matter or what my eye and probably many other eyes are used to seeing. – Ma0 May 15 '17 at 16:11
It appears that [Python documentation](https://docs.python.org/2/library/functions.html?highlight=type#type) recommend the use of isinstance() – Trolldejo May 15 '17 at 16:15
[`type` vs `isinstance`](http://stackoverflow.com/questions/21894575/isinstancefoo-bar-vs-typefoo-is-bar) or better yet [this](http://stackoverflow.com/questions/1549801/differences-between-isinstance-and-type-in-python) – Ma0 May 15 '17 at 16:19

1 Answers1