#python

Handling timezone in Python

UTC, or Coordinated Universal Time, is the primary time standard by which the world regulates date and time.

• astimezone() –> it helps to convert the time of a particular time zone into another time zone
• localtime() –> it helps to get the current local time

Python Decorators

• It’s a very powerful and useful tool in Python
• It allows to add functionality to an existing function or class.

7. Multi-threading

Multithreading allows you to break down an application into multiple sub-tasks and run these tasks simultaneously.

If you use multithreading properly, your application speed, performance, and rendering can all be improved.

Multithreading is defined as the ability of a processor to execute multiple threads concurrently.

Multi Processing

Multiprocessing refers to the ability of a system to support more than one processor at the same time.

Applications in a multiprocessing system are broken to smaller routines that run independently. The operating system allocates these threads to the processors improving performance of the system.

1. OOPs, Concept

• Object Oriented Programming
• OOP is a specific way of designing a program by using classes and objects
• It allows us to relate program with real-world objects, like properties and behaviors
• Properties
  • It defines the state of the object.
  • Like: name, age, address etc. that store data of the object
• Behaviors
  • Are the actions our object can take.
  • Like: talking, breathing, running etc
  • Oftentimes, this involves using or modifying the properties of our object.

2. Variables/Attribute

In a class all the variables are term as Attribute

There are 3 types of variables are allowed.

1. Instance/Regular Variables - - Object Level Variables
2. Class/Static Variables - - Class Level Variables
3. Local variables - - Method Level Variables

• Attributes are looked first in the instance and then in the class

3. Methods in python

• Function
  • Function is block of code that is also called by its name(independent)
  • Function does not deal with Class and its instance concept.
• Methods
  • Method is called by its name, but it is associated to an object (dependent)

The following are various types of allowed methods:

1. Instance Methods - - self
2. Class Methods - - cls
3. Static Methods

Type Checking/Annotations in Python

• Type Annotations are a new feature added in PEP 484 that allow for adding type hints to variables.
• They are used to inform someone reading the code what the type of a variable should be.
• This brings a sense of statically typed control to the dynamically typed Python
• Usage

  • Annotate Argument
  • Annotate Return type
  • Annotate Variable

4.1 Encapsulation in Python

• Access modifier are useful to attain encapsulation
• It is archived by access modifiers public, private, protected

Python does not have strong distinctions between private and public variables like Java does.

There is no private-ness in python, as one of Python principles says –> We're all adults

# They just follow convention
Single underscore `_`
    --> its suppose to be protected
Double underscore `__`
    --> Do not use this field directly

# It is called Name Mangling

5. Inheritance

It is a mechanism that allows you to create a hierarchy of classes that share a set of properties and methods by deriving a class from another class. Inheritance is the capability of one class to derive or inherit the properties from another class.

• It specifies that the child object acquires all the properties and behaviors of the parent object.
• It provides re-usability of the code.