How do I tell what type of data is inside python variable?

Question

I have a list of variables.. inside the list are strings, numbers, and class objects. I need to perform logic based on each different type of data. I am having trouble detecting class objects and branching my logic at that point.

if(type(lists[listname][0]).__name__ == 'str'): # <--- this works for strings
elif(type(lists[listname][0]).__name__ == 'object'): <--- this does not work for classes

in the second line of code above, the name variable contains "Address" as the class name. I was hoping it would contain "class" or "object" so I could branch my program. I will have many different types of objects in the future, so it's a bit impractical to perform logic on every different class name, "Address" "Person" etc

please let me know if my question needs clarification.

thanks!!

Answer 1

FYI: it also makes a difference if its a new-style class or not:

# python
type(1).__name__
'int'
type('1').__name__
'str'
class foo(object):
  pass
type(foo()).__name__
'foo'
class bar:
  pass
type(bar()).__name__
'instance'

If you can make sure they're all new-style classes, your method will determine the real type. If you make them old-style, it'll show up as 'instance'. Not that I'm recommending making everything all old-style just for this.

However, you can take it one step further:

type(bar().__class__).__name__
'classobj'
type(foo().__class__).__name__
'type'

And always look for 'classobj' or 'type'. (Or the name of the metaclass, if it has one.)