Using With Python Libraries || Notes || Sumita Arora || Class 12 || Computer science || Information practices
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Using With Python Libraries
Library: - Library is a collection of modules (and packages) that together cater to a specific type of applications or requirements.
Modules: - The act of partitioning a program
into individual components (known as modules) is called modularity.
A module is a separate unit in itself.
Advantage of module: -
• It reduces its complexity to some degree.
• It creates a number of well defined, documented boundaries within the
program.
• Its contents can be reused in other programs, without having to rewrite or
recreate them.
Python module: - A python module is
a file (.py file) containing
variables, class definitions, statement and functions related to a particular
task.
• The python module that come preloaded with python are called standard library
modules.
Importing Modules in a Python Program
Python provides import statement to import modules in a program. The import
statement can be used in two forms.
(1) To import entire module: the import <module> command
(2) To import selected objects from a module: the from
<module> import <object> command
Importing Entire Module: -
The imports statement can be used to import entire module and even for importing
selected items.
To import entire module syntax is -
import <module 1 >, <module 2>....
For example:
import time
import decimals, fractions
Dot notation :- After importing a
module, to access one of the functions, you have to specify the name of the
module and the name of the function, separated by a dot (also known as a
period) this format is called dot notation.
Syntax: -
<module-name>.<function-name> ()
This way of referring to a module's object is called dot notation.
For example:
import math
math.sqrt(16)
• You can give alias name to imported module as
Syntax :
import <module> as
<alias name>
For Example :-
import math as a
a.sqrt (16)
Importing Select Objects from a Module:
-
If you want to import some selected items, not all from a module, then you can
use following syntax:-
from <module name >import<object name>
For example:
from math import sqrt
To Import Multiple Objects:-
If you want to import multiple objects from the module then you can use
following syntax :-
from <module name >import<object
name>,<object name>,<object name>....
For example: -
from math import sqrt, pi, pow
USING PYTHON STANDARD LIBRARY'S
FUNCTIONS AND MODULES: -
Python's standard library offers many built in functions and modules for specialized
type of functionality.
For example:-
len(),str(),type()
math module, random module , etc.
Using python's built in functions: -
The python interpreter has a number of functions built into it that are always
available, you need not import any module for them.
Python's built in string functions: -
That are ---
• <str>.join (<string
iterable>) - Joins a string or character after each member of the string
iterator.
(I) If the string based iterator is a string then the <str> is inserted
after every character of the string.
For example:
>>>"***".
join ("Hello")
'H***e***l***l***o'
(ii) If the string based iterator is a list or tuple of string then, the given
string / character is joined with each member of the list or tuple, But the
list or tuple must have all member as strings otherwise Python will raise an
error.
>>>"***". join (("Hello", "Python"))
'Hello***Python'
>>>"***". join (["Hello", "Python", "Language"])
'Hello***Python***Language'
>>>"***". join ((123,"Hello","Python"))
Error
• <str>. split (<string/char>)
- Split a string based on given string or character and return a list
containing split strings as members.
(i) If you do not provide any argument to split then by default it will split
the give string considering whitespace as a separator.
For example:
>>>"I Love Python". split()
['I', 'Love', 'Python']
(ii) If you provide a string or a character as an argument to split (),then the
given string is divided into parts considering the given string/character as
separate and separator character is not included in the split string.
For example:
>>>"I Love Python". split ("o")
['I L','ve Pyth','n']
• <str>. replace (<word to be
replaced>,<replace word>) - Replaces a word or part of the string
with another in the given string <str>.
For example:
>>>"I Love Python". replace ("Python", "Programming")
>>>"I Love Programming"
USING RANDOM MODULE: -
Python has a module namely random that provides random number generators.
To use random number generators in your Python program, you first need to
import module random using any import command
import random
Some most common random number generator functions in random module are:
random () : - It returns a random floating point
number N in range [0.0,1.0] , i.e., 0.0 ≤ N ≥ 1.0.
randint (a, b) : - It returns a random integer N
in the range (a, b) , i.e. , a ≤ N ≤ b (both range-limit are inclusive).
random.uniform(a, b) : - It returns a random
floating point number N such that
a ≤ N ≤ b for a ≤ b and
b ≤ N ≤ a for b < a and
random.randrange(stop) or random.randrange(start, stop, [ steps]) : - It returns
a randomly selected element from rang ( start, stop, step ) .
USING STRING MODULE: -
Python has a module by the name string that comes with many constant and
classes.
If you want to use string module, then you must import it by using import command:
-
Like that: -
import string
For example: -
>>>import
string
>>>string.digits
'0123456789'
CREATING A PYTHON LIBRARY: -
Package: - A package is a collection
of Python modules under a common namespace, created by placing different
modules on a single directory along with some special file such (__init__.py).
• A library can have one or more packages and sub-packages.
Steps of making package: -
· At first you have known a path where all files of python saved.
You can find the path of python by following command as shown in figure:-
· Copy that path and paste in computer paths like this: -
· Make a file (package name). For example we make pathwala (package) folder.
· Now make another folder (Sub Package) in package folder; if you want
For example we make portal_express (sub package)
· Now make an empty module with name __init__.py in portal_express (sub package)
And save that module like that:-
Like
that:-
· Similarly also, make an empty module with name __init__.py in pathwala(package)
· Now make modules as you want in pathwala(Package)
For example : We make volume module as shown in figure
And save that module in pathwala (Package)
· Now make modules as you want in portal_express(Sub Package)
For example : We make area module as shown in figure
· And save that module in portal_express (Sub Package)
· Now, Your package become ready to use in Python
For example as shown in figure: -
Thankyou!!!!!
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