62 63 64

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Modules

a group of functions , classes, variables saved in a file called Modules.it is a phython file.

Every phyton file is a module.

x=888

name ='afs'

def add(a,b):

    print(a+b)

def product(a,b):

    print(a*b)

    

    --- save this file as abc.py  then in another file import abc(modulename)

                                            modulename.variablename

                                            modulename.functioname()

    

    biggest advantage is we can use existing module in our file.

  

  Advantage:

    Code Reusability

    Readibiltiy

    Development time

    Cost of Project

    

  Both file should be in same directory ?   generally yes but it can  be in another folder also.

Packages is next level concept.  

From import ?   

for module pyc file generated  . if code changed then pyc file will generated again.

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in last session

what is module 

advantage of module

how to define module and how we can use that module?

Module name aliasing :

==================

import abc as a

a.variablename

a.functionname()

once we define the aliasname then we cannot use original name.

if i donot want to use modulename or aliasname then we have to use From import.

Usually we can acccess members of a module by using module na,e.

If we donot want to use module name then we should go for FROM IMPORT.

From Modulename import x, name

now we can directly use x and name but now cannot use function.

All memeber from module

From modulename import *   ------------ important

Anywhere we cab write import statement.

Member Aliasing

===========

From durgamath import addd as a , product as p

Various Possibilities of Import:

===============================

import module1

import module1, module2, module3

import module1 as m1

import module1 as m1 ,module2 as m2 , module3 as m3

from module1 import member1

from module1 import memeber1, member2, member3

from module1  import *

from module1 import member1 as m1

from module1 import member1 as m1, memeber2 as m2

Module Naming conflicts;

========================

module1

x=10

def add(a,b):

    print('module1')

    print(a+b)

    

module2

y=20

def add(a,b):

    print('module2')

    print(a+b)

    

--- 

from module1 import *

from module2 import *

add(10,20)----------------------------python is always going to consider the most recent copy

In the case of conflicts, python will always consider the most recent copy.

from module1 import *

from module2 import *

def add(a,b):

    print('currnet module')

    print (a+b)

add(10,20)

the most recent copy --order wise which is available at last.

x=10

x=20

x=30

print(x)----30

x

First way

import module1

import module2

module1.add(1,2)

module2.add(1,2)

second way

from module1 import add as a1

from module2 import add as a2

a1(1,20)

a2(22,33)

Reloading of a module:

======================

if you import module multiple times in code , it will be loaded just once.

By default module will be loaded only once eventhough if we are importing multiple times.

Advantage : Performance is more.

Problem : We are missing updations of that module.

there is a imp module having reload function. it is used to reload the module in code.

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Module

Advantage of module

various possibilittes of import

Naming conflicts

module reloading

dir() and help() Functions.

Finding memebers of module by using Dir() function :

===================================================

 To list out member of a module.

 

 dir() ---> to list members of current module.return as list

 dir(modulename) --to listout members of specified module.

 

 a=10

 b=20

 def add(a,b):

    return a+b

   

def product(a,b):

    return a*b

print(dir()) --- will return ['a','b','add','product']

    For every module Python virtual machine will add several predefined variables which are internally used by PVM. Even these variables can be used programmer based on his requirenment.

    

    to list out all memeber of MAth module

    

    dir(math) --- befire using we need to import math module

    

    import math

    print(dir(math)) ---- it will list out all memmber of module varibale +  mehtod now how to identify

    

    help documentation of a module

   =================================

   

   help()

    

    

    how to use help

    import math

    help(math) --- no need to use printm , using help we can identity which is variable and method.

    

   Difference between Dir() and help()

   ===============================

   Dir() is just to get all list of memeber as a list

   help() will give complete documentation of module

   

   

  Extra member added by PVM for every module:

  ============================================

  __doc__

  __file__

  __name__

  __loader__

  .

  .

  print(__annotation__)

  

  __doc__ 

  ========

  this variable hold documentaiton string.

  

  import math

  print(math.__doc__)

  

  import random

  print(random.__doc__)

  

  __File__

  =========

            print(__file__) --- willl return file name

Absolute path to get --

print('Absolute Path',os.path.abspath(__file__))