reflection import - How can I get a list of all classes within current module in Python?




objects functions (9)

I've seen plenty of examples of people extracting all of the classes from a module, usually something like:

# foo.py
class Foo:
    pass

# test.py
import inspect
import foo

for name, obj in inspect.getmembers(foo):
    if inspect.isclass(obj):
        print obj

Awesome.

But I can't find out how to get all of the classes from the current module.

# foo.py
import inspect

class Foo:
    pass

def print_classes():
    for name, obj in inspect.getmembers(???): # what do I do here?
        if inspect.isclass(obj):
            print obj

# test.py
import foo

foo.print_classes()

This is probably something really obvious, but I haven't been able to find anything. Can anyone help me out?


Answers

I was able to get all I needed from the dir built in plus getattr.

# Works on pretty much everything, but be mindful that 
# you get lists of strings back

print dir(myproject)
print dir(myproject.mymodule)
print dir(myproject.mymodule.myfile)
print dir(myproject.mymodule.myfile.myclass)

# But, the string names can be resolved with getattr, (as seen below)

Though, it does come out looking like a hairball:

def list_supported_platforms():
    """
        List supported platforms (to match sys.platform)

        @Retirms:
            list str: platform names
    """
    return list(itertools.chain(
        *list(
            # Get the class's constant
            getattr(
                # Get the module's first class, which we wrote
                getattr(
                    # Get the module
                    getattr(platforms, item),
                    dir(
                        getattr(platforms, item)
                    )[0]
                ),
                'SYS_PLATFORMS'
            )
            # For each include in platforms/__init__.py 
            for item in dir(platforms)
            # Ignore magic, ourselves (index.py) and a base class.
            if not item.startswith('__') and item not in ['index', 'base']
        )
    ))

What about

g = globals().copy()
for name, obj in g.iteritems():

?


I think that you can do something like this.

class custom(object):
    __custom__ = True
class Alpha(custom):
    something = 3
def GetClasses():
    return [x for x in globals() if hasattr(globals()[str(x)], '__custom__')]
print(GetClasses())`

if you need own classes


I don't know if there's a 'proper' way to do it, but your snippet is on the right track: just add import foo to foo.py, do inspect.getmembers(foo), and it should work fine.


This is the line that I use to get all of the classes that have been defined in the current module (ie not imported). It's a little long according to PEP-8 but you can change it as you see fit.

import sys
import inspect

classes = [name for name, obj in inspect.getmembers(sys.modules[__name__], inspect.isclass) 
          if obj.__module__ is __name__]

This gives you a list of the class names. If you want the class objects themselves just keep obj instead.

classes = [obj for name, obj in inspect.getmembers(sys.modules[__name__], inspect.isclass)
          if obj.__module__ is __name__]

This is has been more useful in my experience.


Try this:

import sys
current_module = sys.modules[__name__]

In your context:

import sys, inspect
def print_classes():
    for name, obj in inspect.getmembers(sys.modules[__name__]):
        if inspect.isclass(obj):
            print(obj)

And even better:

clsmembers = inspect.getmembers(sys.modules[__name__], inspect.isclass)

Because inspect.getmembers() takes a predicate.


import pyclbr
print(pyclbr.readmodule(__name__).keys())

Note that the stdlib's Python class browser module uses static source analysis, so it only works for modules that are backed by a real .py file.


Another solution which works in Python 2 and 3:

#foo.py
import sys

class Foo(object):
    pass

def print_classes():
    current_module = sys.modules[__name__]
    for key in dir(current_module):
        if isinstance( getattr(current_module, key), type ):
            print(key)

# test.py
import foo
foo.print_classes()

mylist = [ 1 , 2 , 3 , 4 , 5]

#------------------------------------
# Method-1 : Last index
#------------------------------------

print(mylist[-1])


#------------------------------------
# Method-2 : Using len 
#------------------------------------

print(mylist[len(mylist) - 1])


#------------------------------------
# Method-3 : Using pop, pop will remove the last 
#            element from the list.
#------------------------------------

print(mylist.pop())




python reflection inspect