# Object introspection

## Object introspection

**Introspection: the ability to determine the type of an object at runtime**.

One of Python’s strengths.

**Everything in Python is an object** and **we can examine those objects**. 

## `dir`

Returns a list of attributes and methods belonging to an object. Here is an example:

```python
my_list = [1, 2, 3]
dir(my_list)
# Output: ['__add__', '__class__', '__contains__', '__delattr__', '__delitem__',
# '__delslice__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__',
# '__getitem__', '__getslice__', '__gt__', '__hash__', '__iadd__', '__imul__',
# '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__',
# '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__',
# '__setattr__', '__setitem__', '__setslice__', '__sizeof__', '__str__',
# '__subclasshook__', 'append', 'count', 'extend', 'index', 'insert', 'pop',
# 'remove', 'reverse', 'sort']
```

Introspection gave us the names of all the methods of a list.

`dir()` without any argument then it returns all names in the current scope.

## `type` and `id`

`type` function **returns the type of an object**.

Example:

```python
print(type(''))
# Output: <type 'str'>

print(type([]))
# Output: <type 'list'>

print(type({}))
# Output: <type 'dict'>

print(type(dict))
# Output: <type 'type'>

print(type(3))
# Output: <type 'int'>
```

`id` **returns the unique ids of various objects**.

Example:

```python
name = "Yasoob"
print(id(name))
# Output: 139972439030304
```

## **`inspect` module**

**Provides several useful functions to get information about live objects**.

Example:  check the members of an object by running:

```python
import inspect
print(inspect.getmembers(str))
# Output: [('__add__', <slot wrapper '__add__' of ... ...
```