Code Introspection in Python

Introspection is an act of self-examination. It is the ability to examine classes, functions and keywords to know what they are, what they do and what they know.

It is used for examining the classes, methods, objects, modules, keywords to get information about them so that we can utilize it. Introspection reveals useful information about objects. Python is a dynamic, object-oriented programming language, that provides tremendous introspection support. It support for introspection runs deep and wide throughout the language. Python provides some built-in functions that are used for code introspection, they are:

1. type()

In this function return which type of an object. 

a = [1,2,3,4,"abc"]
print(type(a))
print(type(a[0]))
print(type(a[4]))

Output:

<class 'list'>
<class 'int'>
<class 'str'>

2. dir()

It return list of methods and attributes associated with the particular  object.

a = ['a','b','c','d']
print(dir(a))

Output:

['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__dir__',
'__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', 
'__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__init_subclass__', 
'__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', 
'__reduce__', '__reduce_ex__', '__repr__', '__reversed__', '__rmul__', 
'__setattr__', '__setitem__', '__sizeof__', '__str__', '__subclasshook__', 
'append', 'clear', 'copy', 'count', 'extend', 'index', 'insert', 'pop', 
'remove', 'reverse', 'sort']

3. str()

It is used to convert everything into a string.

a = 3
print(type(a))

a = str(a)
print(a)

print(type(a))

Output:

<class 'int'>
3
<class 'str'>

4. id()

It is used to return a special id assigned to the object.

a = [1,2,3,4,5]
print(id(a))

Output: 140426128161216