如何获取Python类中的方法列表？

I want to iterate through the methods in a class, or handle class or instance objects differently based on the methods present. How do I get a list of class methods?

Also see:

• How can I list the methods in a Python 2.5 module?
• Looping over a Python / IronPython Object Methods
• Finding the methods an object has
• How do I look inside a Python object?
• How Do I Perform Introspection on an Object in Python 2.x?
• How to get a complete list of object’s methods and attributes?
• Finding out which functions are available from a class instance in python?

An example (listing the methods of the optparse.OptionParser class):

>>> from optparse import OptionParser
>>> import inspect
#python2
>>> inspect.getmembers(OptionParser, predicate=inspect.ismethod)
[([('__init__', <unbound method OptionParser.__init__>),
...
 ('add_option', <unbound method OptionParser.add_option>),
 ('add_option_group', <unbound method OptionParser.add_option_group>),
 ('add_options', <unbound method OptionParser.add_options>),
 ('check_values', <unbound method OptionParser.check_values>),
 ('destroy', <unbound method OptionParser.destroy>),
 ('disable_interspersed_args',
  <unbound method OptionParser.disable_interspersed_args>),
 ('enable_interspersed_args',
  <unbound method OptionParser.enable_interspersed_args>),
 ('error', <unbound method OptionParser.error>),
 ('exit', <unbound method OptionParser.exit>),
 ('expand_prog_name', <unbound method OptionParser.expand_prog_name>),
 ...
 ]
# python3
>>> inspect.getmembers(OptionParser, predicate=inspect.isfunction)
...

Notice that getmembers returns a list of 2-tuples. The first item is the name of the member, the second item is the value.

You can also pass an instance to getmembers:

>>> parser = OptionParser()
>>> inspect.getmembers(parser, predicate=inspect.ismethod)
...

There is the dir(theobject) method to list all the fields and methods of your object (as a tuple) and the inspect module (as codeape write) to list the fields and methods with their doc (in “””).

Because everything (even fields) might be called in Python, I’m not sure there is a built-in function to list only methods. You might want to try if the object you get through dir is callable or not.

Python 3.x answer without external libraries

method_list = [func for func in dir(Foo) if callable(getattr(Foo, func))]

dunder-excluded result:

method_list = [func for func in dir(Foo) if callable(getattr(Foo, func)) and not func.startswith("__")]

Say you want to know all methods associated with list class Just Type The following

 print (dir(list))

Above will give you all methods of list class

Try the property __dict__.

you can also import the FunctionType from types and test it with the class.__dict__:

from types import FunctionType

class Foo:
    def bar(self): pass
    def baz(self): pass

def methods(cls):
    return [x for x, y in cls.__dict__.items() if type(y) == FunctionType]

methods(Foo)  # ['bar', 'baz']

Note that you need to consider whether you want methods from base classes which are inherited (but not overridden) included in the result. The dir() and inspect.getmembers() operations do include base class methods, but use of the __dict__ attribute does not.

This also works:

mymodule.py

def foo(x)
   return 'foo'
def bar()
   return 'bar'

In another file

import inspect
import mymodule
method_list = [ func[0] for func in inspect.getmembers(mymodule, predicate=inspect.isroutine) if callable(getattr(mymodule, func[0])) ]

output:

['foo', 'bar']

From the python docs:

inspect.isroutine(object)

Return true if the object is a user-defined or built-in function or method.

def find_defining_class(obj, meth_name):
    for ty in type(obj).mro():
        if meth_name in ty.__dict__:
            return ty

So

print find_defining_class(car, 'speedometer') 

Think Python page 210

There’s this approach:

[getattr(obj, m) for m in dir(obj) if not m.startswith('__')]

When dealing with a class instance, perhaps it’d be better to return a list with the method references instead of just names¹. If that’s your goal, as well as

1. Using no import
2. Excluding private methods (e.g. __init__) from the list

It may be of use. In a nutshell, for a class like

class Ghost:
    def boo(self, who):
        return f'Who you gonna call? {who}'

We could check instance retrieval with

>>> g = Ghost()
>>> methods = [getattr(g, m) for m in dir(g) if not m.startswith('__')]
>>> print(methods)
[<bound method Ghost.boo of <__main__.Ghost object at ...>>]

So you can call it right away:

>>> for method in methods:
...     print(method('GHOSTBUSTERS'))
...
Who you gonna call? GHOSTBUSTERS

¹ An use case:

I used this for unit testing. Had a class where all methods performed variations of the same process – which led to lengthy tests, each only a tweak away from the others. DRY was a far away dream.

Thought I should have a single test for all methods, so I made the above iteration.

Although I realized I should instead refactor the code itself to be DRY-compliant anyway… this may still serve a random nitpicky soul in the future.

I just keep this there, because top rated answers are not clear.

This is simple test with not usual class based on Enum.

# -*- coding: utf-8 -*-
import sys, inspect
from enum import Enum

class my_enum(Enum):
    """Enum base class my_enum"""
    M_ONE = -1
    ZERO = 0
    ONE = 1
    TWO = 2
    THREE = 3

    def is_natural(self):
            return (self.value > 0)
    def is_negative(self):
            return (self.value < 0)

def is_clean_name(name):
    return not name.startswith('_') and not name.endswith('_')
def clean_names(lst):
    return [ n for n in lst if is_clean_name(n) ]
def get_items(cls,lst):
    try:
            res = [ getattr(cls,n) for n in lst ]
    except Exception as e:
            res = (Exception, type(e), e)
            pass
    return res


print( sys.version )

dir_res = clean_names( dir(my_enum) )
inspect_res = clean_names( [ x[0] for x in inspect.getmembers(my_enum) ] )
dict_res = clean_names( my_enum.__dict__.keys() )

print( '## names ##' )
print( dir_res )
print( inspect_res )
print( dict_res )

print( '## items ##' )
print( get_items(my_enum,dir_res) )
print( get_items(my_enum,inspect_res) )
print( get_items(my_enum,dict_res) )

And this is output results.

3.7.7 (default, Mar 10 2020, 13:18:53) 
[GCC 9.2.1 20200306]
## names ##
['M_ONE', 'ONE', 'THREE', 'TWO', 'ZERO']
['M_ONE', 'ONE', 'THREE', 'TWO', 'ZERO', 'name', 'value']
['is_natural', 'is_negative', 'M_ONE', 'ZERO', 'ONE', 'TWO', 'THREE']
## items ##
[<my_enum.M_ONE: -1>, <my_enum.ONE: 1>, <my_enum.THREE: 3>, <my_enum.TWO: 2>, <my_enum.ZERO: 0>]
(<class 'Exception'>, <class 'AttributeError'>, AttributeError('name'))
[<function my_enum.is_natural at 0xb78a1fa4>, <function my_enum.is_negative at 0xb78ae854>, <my_enum.M_ONE: -1>, <my_enum.ZERO: 0>, <my_enum.ONE: 1>, <my_enum.TWO: 2>, <my_enum.THREE: 3>]

So what we have:

• dir provide not complete data
• inspect.getmembers provide not complete data and provide internal keys that are not accessible with getattr()
• __dict__.keys() provide complete and reliable result

Why are votes so erroneous? And where i’m wrong? And where wrong other people which answers have so low votes?

methods = [(func, getattr(o, func)) for func in dir(o) if callable(getattr(o, func))]

gives an identical list as

methods = inspect.getmembers(o, predicate=inspect.ismethod)

does.

If your method is a “regular” method and not a statimethod, classmethod etc.
There is a little hack I came up with –

for k, v in your_class.__dict__.items():
    if "function" in str(v):
        print(k)

This can be extended to other type of methods by changing “function” in the if condition correspondingly.
Tested on python 2.7.

You can list all methods in a python class by using the following code

dir(className)

This will return a list of all the names of the methods in the class

I know this is an old post, but just wrote this function and will leave it here is case someone stumbles looking for an answer:

def classMethods(the_class,class_only=False,instance_only=False,exclude_internal=True):

    def acceptMethod(tup):
        #internal function that analyzes the tuples returned by getmembers tup[1] is the 
        #actual member object
        is_method = inspect.ismethod(tup[1])
        if is_method:
            bound_to = tup[1].im_self
            internal = tup[1].im_func.func_name[:2] == '__' and tup[1].im_func.func_name[-2:] == '__'
            if internal and exclude_internal:
                include = False
            else:
                include = (bound_to == the_class and not instance_only) or (bound_to == None and not class_only)
        else:
            include = False
        return include
    #uses filter to return results according to internal function and arguments
    return filter(acceptMethod,inspect.getmembers(the_class))

This is just an observation. “encode” seems to be a method for string objects

str_1 = 'a'
str_1.encode('utf-8')
>>> b'a'

However, if str1 is inspected for methods, an empty list is returned

inspect.getmember(str_1, predicate=inspect.ismethod)
>>> []

So, maybe I am wrong, but the issue seems to be not simple.

class CPerson:
    def __init__(self, age):
        self._age = age

    def run(self):
        pass

    @property
    def age(self): return self._age

    @staticmethod
    def my_static_method(): print("Life is short, you need Python")

    @classmethod
    def say(cls, msg): return msg


test_class = CPerson
# print(dir(test_class))  # list all the fields and methods of your object
print([(name, t) for name, t in test_class.__dict__.items() if type(t).__name__ == 'function' and not name.startswith('__')])
print([(name, t) for name, t in test_class.__dict__.items() if type(t).__name__ != 'function' and not name.startswith('__')])

output

[('run', <function CPerson.run at 0x0000000002AD3268>)]
[('age', <property object at 0x0000000002368688>), ('my_static_method', <staticmethod object at 0x0000000002ACBD68>), ('say', <classmethod object at 0x0000000002ACF0B8>)]

If you want to list only methods of a python class

import numpy as np
print(np.random.__all__)