Introduction To Python
Object Oriented Programming
Object-oriented programming
• Python is an object-oriented programming language.
• Unlike Java, Python doesn't force you t...
The class Statement
Syntax:
class classname:
statement(s)
Example:
Class baabtra :
def hello(self) :
print "Hello"
A metho...
Instances
Syntax
anInstance = Class_name( )
Example
baabObject = baabtra( )
_ _init_ _
• When a class has a method named _ _init_ _, calling the class object
implicitly executes _ _init_ _ on the ne...
Inheritance
Syntax
Derived_class(Base class_name[,Base class_name1][,Base class_name2][,...])
Example
class Baabte:
def am...
Modules
• A typical Python program is made up of several source files. Each
source file corresponds to a module, which pac...
The import Statement
Syntax
import modname [as varname][,...]
Example
import MyModule1
import MyModule as Alias
The import Statement
Syntax
import modname [as varname][,...]
Example
import MyModule1
import MyModule as Alias
In the sim...
The import Statement
Syntax
import modname [as varname][,...]
Example
import MyModule1
import MyModule as Alias
looks for ...
The from Statement
Syntax
from modname import attrname [as varname][,...]
from modname import *
example
• from MyModule im...
The from Statement
Syntax
from modname import attrname [as varname][,...]
from modname import *
example
• from MyModule im...
The Relative import
employees
employeeDetails.py
HRAccounts
My_project
userBill.py
Suppose we are here and we want to
impo...
The Relative import
employees
employeeDetails.py
HRAccounts
My_project
userBill.py
import sys
import os
str_current_path =...
The Relative import
sys.path
– A list of strings that specifies the search path for modules
sys.path.append( module path )...
_ _ main _ _
• When the Python interpreter reads a source file, it executes all of the code found
in it. But Before execut...
def func():
print("func() in one.py")
print("top-level in one.py")
if __name__ == "__main__":
print("one.py is being run d...
def func():
print("func() in one.py")
print("top-level in one.py")
if __name__ == "__main__":
print("one.py is being run d...
def func():
print("func() in one.py")
print("top-level in one.py")
if __name__ == "__main__":
print("one.py is being run d...
Questions?
“A good question deserve a good grade…”
Want to learn more about programming or Looking to become a good programmer?
Are you wasting time on searching so many con...
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Like us @ facebook.com/baabtra
Subscribe to us @ youtube.com/baabtra
Become a follower @ s...
Contact Us
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Mavoor Road, Kozhikode,
Kerala, India.
Ph: + 91 – 495 40 25 550
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Object oriented programming in python

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Object oriented programming in python

  1. 1. Introduction To Python Object Oriented Programming
  2. 2. Object-oriented programming • Python is an object-oriented programming language. • Unlike Java, Python doesn't force you to use the object-oriented paradigm exclusively. • Python also supports procedural programming with modules and functions, so you can select the most suitable programming paradigm for each part of your program. “Generally, the object-oriented paradigm is suitable when you want to group state (data) and behavior (code) together in handy packets of functionality.”
  3. 3. The class Statement Syntax: class classname: statement(s) Example: Class baabtra : def hello(self) : print "Hello" A method defined inside a class body will always have a mandatory first parameter, conventionally named self, that refers to the instance on which you call the method.
  4. 4. Instances Syntax anInstance = Class_name( ) Example baabObject = baabtra( )
  5. 5. _ _init_ _ • When a class has a method named _ _init_ _, calling the class object implicitly executes _ _init_ _ on the new instance to perform any instance-specific initialization that is needed. class baabtra: def _ _init_ _(self,n): self.x = n baabtraInstance = baabtra(42)
  6. 6. Inheritance Syntax Derived_class(Base class_name[,Base class_name1][,Base class_name2][,...]) Example class Baabte: def amethod(self): print "Baaabte" class Baabtra(Baabte): def amethod(self): print "Baabtra“ aninstance = Baaabtra ( ) aninstance.amethod( ) # prints Baabtra
  7. 7. Modules • A typical Python program is made up of several source files. Each source file corresponds to a module, which packages program code and data for reuse. • Modules are normally independent of each other so that other programs can reuse the specific modules they need. • A module explicitly establishes dependencies upon another module by using import or from statements.
  8. 8. The import Statement Syntax import modname [as varname][,...] Example import MyModule1 import MyModule as Alias
  9. 9. The import Statement Syntax import modname [as varname][,...] Example import MyModule1 import MyModule as Alias In the simplest and most common case, modname is an identifier, the name of a variable that Python binds to the module object when the import statement finishes
  10. 10. The import Statement Syntax import modname [as varname][,...] Example import MyModule1 import MyModule as Alias looks for the module named MyModule and binds the variable named Alias in the current scope to the module object. varname is always a simple identifier.
  11. 11. The from Statement Syntax from modname import attrname [as varname][,...] from modname import * example • from MyModule import f
  12. 12. The from Statement Syntax from modname import attrname [as varname][,...] from modname import * example • from MyModule import f Importing only one attribut which is named as ‘f’
  13. 13. The Relative import employees employeeDetails.py HRAccounts My_project userBill.py Suppose we are here and we want to import the file empleeDetails.py which resides in a directory as shown
  14. 14. The Relative import employees employeeDetails.py HRAccounts My_project userBill.py import sys import os str_current_path = os.getcwd() ## get current working directory str_module_path = str_current_path.replace( ' Accounts',‘HR/employees / ') sys.path.append( str_module_path ) import employeeDetails
  15. 15. The Relative import sys.path – A list of strings that specifies the search path for modules sys.path.append( module path ) – This statement append our module path with the existing list of sys.path, then the import statement search for the module in the module path as we specified.
  16. 16. _ _ main _ _ • When the Python interpreter reads a source file, it executes all of the code found in it. But Before executing the code, it will define a few special variables. • For example, if the python interpreter is running a module (the source file) as the main program, it sets the special __name__ variable to have a value"__main__". • If this file is being imported from another module, __name__ will be set to the module's name.
  17. 17. def func(): print("func() in one.py") print("top-level in one.py") if __name__ == "__main__": print("one.py is being run directly") else: print("one.py is being imported into another module") import one print("top-level in two.py") one.func() if __name__ == "__main__": print("two.py is being run directly") else: print("two.py is being imported into another module") # file two.py# file one.py Example
  18. 18. def func(): print("func() in one.py") print("top-level in one.py") if __name__ == "__main__": print("one.py is being run directly") else: print("one.py is being imported into another module") import one print("top-level in two.py") one.func() if __name__ == "__main__": print("two.py is being run directly") else: print("two.py is being imported into another module") # file two.py# file one.py Example When we run one.py ----------------------------- Top-level in one.py One.py is being run directly
  19. 19. def func(): print("func() in one.py") print("top-level in one.py") if __name__ == "__main__": print("one.py is being run directly") else: print("one.py is being imported into another module") import one print("top-level in two.py") one.func() if __name__ == "__main__": print("two.py is being run directly") else: print("two.py is being imported into another module") # file two.py# file one.py Example When we run two.py ----------------------------- Top-level in one.py one.py is being imported into another module Top-level in two.py Func() in one.py two.py is being run directly
  20. 20. Questions? “A good question deserve a good grade…”
  21. 21. Want to learn more about programming or Looking to become a good programmer? Are you wasting time on searching so many contents online? Do you want to learn things quickly? Tired of spending huge amount of money to become a Software professional? Do an online course @ baabtra.com We put industry standards to practice. Our structured, activity based courses are so designed to make a quick, good software professional out of anybody who holds a passion for coding.
  22. 22. Follow us @ twitter.com/baabtra Like us @ facebook.com/baabtra Subscribe to us @ youtube.com/baabtra Become a follower @ slideshare.net/BaabtraMentoringPartner Connect to us @ in.linkedin.com/in/baabtra Thanks in advance. www.baabtra.com | www.massbaab.com |www.baabte.com
  23. 23. Contact Us Emarald Mall (Big Bazar Building) Mavoor Road, Kozhikode, Kerala, India. Ph: + 91 – 495 40 25 550 NC Complex, Near Bus Stand Mukkam, Kozhikode, Kerala, India. Ph: + 91 – 495 40 25 550 Cafit Square, Hilite Business Park, Near Pantheerankavu, Kozhikode Ph:9895767088 Start up Village Eranakulam, Kerala, India. Email: info@baabtra.com
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