Iterate Over Object Attributes in Python

Iterate over object attributes in python

Assuming you have a class such as

>>> class Cls(object):
...     foo = 1
...     bar = 'hello'
...     def func(self):
...         return 'call me'
...
>>> obj = Cls()

calling dir on the object gives you back all the attributes of that object, including python special attributes. Although some object attributes are callable, such as methods.

>>> dir(obj)
['__class__', '__delattr__', '__dict__', '__doc__', '__format__', '__getattribute__', '__hash__', '__init__', '__module__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'bar', 'foo', 'func']

You can always filter out the special methods by using a list comprehension.

>>> [a for a in dir(obj) if not a.startswith('__')]
['bar', 'foo', 'func']

or if you prefer map/filters.

>>> filter(lambda a: not a.startswith('__'), dir(obj))
['bar', 'foo', 'func']

If you want to filter out the methods, you can use the builtin callable as a check.

>>> [a for a in dir(obj) if not a.startswith('__') and not callable(getattr(obj, a))]
['bar', 'foo']

You could also inspect the difference between your class and its instance object using.

>>> set(dir(Cls)) - set(dir(object))
set(['__module__', 'bar', 'func', '__dict__', 'foo', '__weakref__'])

Python iterating through object attributes

UPDATED

For python 3, you should use items() instead of iteritems()

PYTHON 2

for attr, value in k.__dict__.iteritems():
        print attr, value

PYTHON 3

for attr, value in k.__dict__.items():
        print(attr, value)

This will print

'names', [a list with names]
'tweet', [a list with tweet]

iterate over an instance object's attributes in Python

There's actually a very simple way to do this, using getattr in place of eval:

myClass = MyClass()
for a in dir(myClass):
    if(a[:2] != "__"): #don't print double underscore methods
        print a, getattr(myClass, a)

Output:

a 7
aAndB 9
b 2

This has the very big advantage of not needing to hard code in the name of your instance into the string, as is required using eval("myClass.{}".format(a))

Looping through an object's (class instance) properties in python and printing them

Try not using private __dict__,
you have python built-in function called vars()

def print_properties(self):
    for prop, value in vars(self).items():
        print(prop, ":", value) # or use format

Explantion of vars, from pythom offical docs:

Return the __dict__ attribute for a module, class, instance, or any
other object with a __dict__ attribute.

Objects such as modules and instances have an updateable __dict__
attribute; however, other objects may have write restrictions on their
__dict__ attributes (for example, new-style classes use a dictproxy to prevent direct dictionary updates).

Without an argument, vars() acts like locals(). Note, the locals
dictionary is only useful for reads since updates to the locals
dictionary are ignored.

How to iterate through attributes of an object defined by getters or @property?

You can use dir() to get all the attributes, though that will include methods inherited from base classes, including all the dunder methods from object:

class MyClass:

    def __init__(self):
        self.foo = "bar"

    @property
    def myprop(self):
        return "hello"

my_instance = MyClass()

for i in dir(my_instance):
    print("object has attribute %s" % i)

prints:

object has attribute __class__
object has attribute __delattr__
object has attribute __dict__
object has attribute __dir__
object has attribute __doc__
object has attribute __eq__
object has attribute __format__
object has attribute __ge__
object has attribute __getattribute__
object has attribute __gt__
object has attribute __hash__
object has attribute __init__
object has attribute __init_subclass__
object has attribute __le__
object has attribute __lt__
object has attribute __module__
object has attribute __ne__
object has attribute __new__
object has attribute __reduce__
object has attribute __reduce_ex__
object has attribute __repr__
object has attribute __setattr__
object has attribute __sizeof__
object has attribute __str__
object has attribute __subclasshook__
object has attribute __weakref__
object has attribute foo
object has attribute myprop

You can exclude some with string operations:

for i in dir(my_instance):
    if i.startswith("__"):
        continue
    print("object has attribute %s" % i)

prints:

object has attribute foo
object has attribute myprop

Iterate over unknown object attributes in Python

As @TheSoundDefense suggested you can use the vars() built-in to list all the attributes of the object. The following answer extends the idea with an example of using it in your case

Implementation

class Foo(object):
    def __init__(self, dictionary):
        for k, v in dictionary.iteritems():
            setattr(self, k, v)
    def __iter__(self):
        return iter(vars(self))

Demo

foo = Foo({'X':1, 'Y':2, 'Z':3})
for elem in foo:
    print elem

Output

Y
X
Z

How to iterate over object attributes and check for duplicate in python?

The code is returning too early. You need to move else part out of the loop to iterate all templates:

for template in templates:
    if template.temp_name == temp_name:
        data = {'status': 'exists'}
        return JsonResponse(data)
data = {'status': 'exist_not'}
return JsonResponse(data)

BTW, you don't need to use loop. Use QuerySet.filter to check whether there is matching template exist:

temp_name = request.POST.get('temp_name')
exists = EmailTemplate.objects.filter(temp_name=temp_name).exists()
data = {'status': 'exists' if exists else 'exist_not'}
return JsonResponse(data)

Iterate over an object's public attributes

You can prepare list of "public" attributes (as list or as generator) before:

>>> public_props = (name for name in dir(object) if not name.startswith('_'))
>>> for name in public_props:
    print name

But please read a note about dir() function in the documentation:

Note Because dir() is supplied primarily as a convenience for use at an interactive prompt, it tries to supply an interesting set of names more than it tries to supply a rigorously or consistently defined set of names, and its detailed behavior may change across releases. For example, metaclass attributes are not in the result list when the argument is a class.

You should also be aware, that any class can implement __dir__() method that may return a list of names that do not necessarily correspond to the names of the attributes. In other words, dir(something) does not guarantee that the result will return attributes of something.

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