Code introspection in Python

Introspection is an ability to determine the type of an object at runtime. Everything in python is an object. Every object in Python may have attributes and methods. By using introspection, we can dynamically examine python objects. Code Introspection is used for examining the classes, methods, objects, modules, keywords and get information about them so that we can utilize it. Introspection reveals useful information about your program’s objects. Python, being a dynamic, object-oriented programming language, provides tremendous introspection support. Python’s 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() : This function returns the type of an object.

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# Python program showing
# a use of type function
  
import math
  
# print type of math
print(type(math))
   
# print type of 1 
print(type(1))
  
# print type of "1"
print(type("1"))
  
# print type of rk
rk =[1, 2, 3, 4, 5, "radha"]
  
print(type(rk))
print(type(rk[1]))
print(type(rk[5]))

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Output:


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



 

2.dir() :This function return list of methods and attributes associated with that object.











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# Python program showing 


# a use of dir() function 


  


import math 


rk =[1, 2, 3, 4, 5] 


  


# print methods and attributes of rk 


print(dir(rk)) 


rk =(1, 2, 3, 4, 5) 


  


# print methods and attributes of rk 


print(dir(rk)) 


rk ={1, 2, 3, 4, 5} 


  


print(dir(rk)) 


print(dir(math)) 



















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Output:


['__add__', '__class__', '__contains__', '__delattr__', '__delitem__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__gt__', '__hash__', '__iadd__', '__imul__', '__init__', '__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']
['__add__', '__class__', '__contains__', '__delattr__', '__dir__', '__doc__', '__eq__', '__format__', '__ge__', '__getattribute__', '__getitem__', '__getnewargs__', '__gt__', '__hash__', '__init__', '__iter__', '__le__', '__len__', '__lt__', '__mul__', '__ne__', '__new__', '__reduce__', '__reduce_ex__', '__repr__', '__rmul__', '__setattr__', '__sizeof__', '__str__', '__subclasshook__', 'count', 'index']
['__doc__', '__loader__', '__name__', '__package__', '__spec__', 'acos', 'acosh', 'asin', 'asinh', 'atan', 'atan2', 'atanh', 'ceil', 'copysign', 'cos', 'cosh', 'degrees', 'e', 'erf', 'erfc', 'exp', 'expm1', 'fabs', 'factorial', 'floor', 'fmod', 'frexp', 'fsum', 'gamma', 'gcd', 'hypot', 'inf', 'isclose', 'isfinite', 'isinf', 'isnan', 'ldexp', 'lgamma', 'log', 'log10', 'log1p', 'log2', 'modf', 'nan', 'pi', 'pow', 'radians', 'sin', 'sinh', 'sqrt', 'tan', 'tanh', 'trunc']





 

3.str() :This function converts everything into a string .











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# Python program showing 


# a use of str() function 


  


a = 1


print(type(a)) 


  


# converting integer 


# into string 


a = str(a) 


print(type(a)) 


  


s =[1, 2, 3, 4, 5] 


print(type(s)) 


  


# converting list 


# into string 


s = str(s) 


print(type(s)) 



















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Output:


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



 

4.id() :This function returns a special id of an object.











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# Python program showing 


# a use of id() function 


   


import math 


a =[1, 2, 3, 4, 5] 


   


# print id of a 


print(id(a)) 


b =(1, 2, 3, 4, 5) 


   


# print id of b 


print(id(b)) 


c ={1, 2, 3, 4, 5} 


   


# print id of c 


print(id(c)) 


print(id(math)) 



















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Output:


139787756828232
139787757942656
139787757391432
139787756815768



Methods for Code Introspection





Function
Description




help()
 It is used it to find what other functions do




hasattr()
Checks if an object has an attribute




getattr()
Returns the contents of an attribute if there are some.




repr()
Return string representation of object




callable()
Checks if an object is a callable object (a function)or not.




issubclass()
Checks if a specific class is a derived class of another class.




isinstance()
Checks if an objects is an instance of a specific class.




sys()
Give access to system specific variables and functions




__doc__
Return some documentation about an object




__name__
Return the name of the object.






          
          
          
          

            

    

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