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.
# 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])) |
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.
# 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)) |
['__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 .
# Python program showing # a use of str() function a = 1print(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)) |
Output:
<class 'int'> <class 'str'> <class 'list'> <class 'str'>
4.id() :This function returns a special id of an object.
# 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)) |
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. |
