# Python Introspection

> Learn how introspection works in Python, using help(), type(), dir(), and id() to inspect functions and objects, plus the inspect module for more detail.

Author: [Flavio Copes](https://flaviocopes.com/about/) | Published: 2021-01-20 | Topics: [Python](https://flaviocopes.com/tags/python/) | Canonical: https://flaviocopes.com/python-introspection/

Functions, variables and objects can be analyzed using **introspection**.

First, using the `help()` global function we can get the documentation if provided in form of docstrings.

Then, you can use print() to get information about a function:

```python
def increment(n):
    return n + 1

print(increment)

# <function increment at 0x7f420e2973a0>
```

or an object:

```python
class Dog():
    def bark(self):
        print('WOF!')

roger = Dog()

print(roger)

# <__main__.Dog object at 0x7f42099d3340>
```

The `type()` function gives us the type of an object:

```python
print(type(increment))
# <class 'function'>

print(type(roger))
# <class '__main__.Dog'>

print(type(1))
# <class 'int'>

print(type('test'))
# <class 'str'>
```

The `dir()` global function lets us find out all the methods and attributes of an object:

```python
print(dir(roger))

# ['__class__', '__delattr__', '__dict__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__gt__', '__hash__', '__init__', '__init_subclass__', '__le__', '__lt__', '__module__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', '__weakref__', 'bark']
```

The `id()` global function shows us the location in memory of any object:

```python
print(id(roger)) # 140227518093024
print(id(1))     # 140227521172384
```

It can be useful to check if two variables point to the same object.

The `inspect` standard library module gives us more tools to get information about objects, and you can check it out here: https://docs.python.org/3/library/inspect.html