PYTHON

 INTRODUCTION

• Python is a high-level, interpreted programming language that is designed to be easy to read and write. It was created by Guido van Rossum in the late 1980s and was first released in 1991.
• like perl, python source code is also available under the GNU General Public License(GPL).
• It has since become one of the most popular programming languages in the world, with a large and active community of users and developers.

Here are many advantages to learning Python, including:

1. Easy to learn: Python has a simple and intuitive syntax that is easy to learn, even for those with no prior programming experience. It emphasizes readability, making it easier to write and maintain code.

2. Versatile: Python can be used for a wide range of tasks, including web development, scientific computing, data analysis, artificial intelligence, and more. This versatility makes it a popular choice for a wide variety of projects and applications.

3. Large and active community: Python has a large and active community of users and developers, who provide a wealth of resources and support for the language. Additionally, many third-party libraries and modules are available for use in Python, making adding functionality to your projects easier.

4. High-level language: Python is a high-level language, which means that it provides higher-level abstractions and is less concerned with low-level details, such as memory management. This makes it easier to write complex programs and to work with large amounts of data.

Rapid development: With Python, you can write code quickly and efficiently, as the language has many built-in functions and libraries, as well as a large number of third-party libraries available, making it easier to get things done.

6. Job market demand: Python is in high demand in the job market, especially in the areas of data science, machine learning, and artificial intelligence. Having Python skills on your resume can increase your chances of finding a well-paying and fulfilling job.

7. Interoperability: Python can easily integrate with other programming languages and can be used in a wide range of environments, including on the web, on the desktop, and on mobile devices. This makes it a flexible language that can be used in various applications.

Learning Python can open up new opportunities and help you become a more well-rounded and versatile programmer.

characteristics of Python:

1. High-level language: Python is a high-level language, which means that it provides higher-level abstractions and is less concerned with low-level details, such as memory management. This makes it easier to write complex programs and to work with large amounts of data.

2. Interpreted language: Python is an interpreted language, which means that it is executed line by line rather than being compiled into machine code. This makes it easier to debug and test code, as well as makes the development process faster and more efficient.

3. Dynamically typed: Python is dynamically typed, which means that the type of a variable is determined at runtime rather than at compile time. This makes it easier to write flexible and reusable code, as well as making it easier to work with changing data types.

4. Object-oriented: Python supports object-oriented programming, which allows you to create reusable and modular code by defining objects and classes. This makes it easier to write large and complex programs and encapsulate data and behavior.

5. Easy to read: Python has a clean and readable syntax, which makes it easy to write code that is easy to understand and maintain. It also supports clear and concise code, making it easier to write code that is both efficient and effective.

6. Large and active community: Python has a large and active community of users and developers, who provide a wealth of resources and support for the language. Additionally, many third-party libraries and modules are available for use in Python, making adding functionality to your projects easier.

Python has a wide range of applications and is used in many different industries and fields. Some of the most common uses of Python include:

Web development: Python is widely used for web development, as it has several frameworks, such as Django and Flask, that make it easier to build and deploy web applications.

Scientific computing and data analysis: Python is a popular choice for scientific computing and data analysis, as it has a large number of libraries, such as NumPy, SciPy, and pandas, that provide support for numerical computation, data analysis, and visualization.

PYTHON VARIABLES:-

In Python, a variable is a container for storing a value. Variables are used to store and manipulate data in programs. They are created by assigning a value to a name using the equals sign =.

For example, you can create a variable called x and assign it the value of 5 like this:

Now, the value of 5 is stored in the variable x. You can use this variable later in your program to perform operations or manipulate the value.

Python variables have some rules that should be followed:

• A variable name must start with a letter or underscore character, and can be followed by any combination of letters, digits, and underscores.
• Variable names are case-sensitive, meaning 'my_var' and 'My_Var' are two different variables.
• It's good practice to use descriptive names for your variables to make your code more readable.

In Python, you don't need to declare the type of the variable before using it, as Python is a dynamically-typed language. This means that the type of the variable is determined at runtime, based on the value it is assigned. For example, if you assign a string value to a variable, the variable will be of type 'str'. If you assign a number to a variable, the variable will be of type 'int' or 'float', depending on the type of number.

DATA TYPES:-

In Python, there are several built-in data types. These data types are used to store and manipulate different kinds of data. Some of the commonly used data types in Python are:

1. Numeric Types: Numeric types are used to store numeric values like integers, floating-point numbers, and complex numbers. Examples of numeric types are int, float, and complex.

2. String Type: String type is used to store a sequence of characters. Strings are enclosed in single or double quotes. Example: "hello world"

3. Boolean Type: Boolean type is used to represent True and False values. Example: True, False.

4. Sequence Types: Sequence types are used to store a collection of items. Examples of sequence types are list, tuple, and range.

5. Set Types: Set types are used to store a collection of unique items. Example: set.

6. Mapping Types: Mapping types are used to store a collection of key-value pairs. Example: dict.

7. File Type: File type is used to work with files on the system. Example: file.

In Python, the data type of a variable is determined dynamically, based on the value it is assigned. You can check the type of a variable using the type() function. For example:

In addition to the built-in data types, Python also supports creating user-defined data types using classes.

BASIC SYNTAX OF PYTHON:-

The basic syntax of Python is simple and easy to learn. Here are some key points to keep in mind:

1. Indentation: Python uses indentation to indicate blocks of code. Blocks are defined by the level of indentation, and they must be consistent throughout the code. A standard convention is to use four spaces for each level of indentation.

2. Statements: Python programs are made up of one or more statements. Each statement is typically written on a separate line.

3. Comments: Comments are used to document the code and make it more readable. In Python, comments start with the # symbol and continue until the end of the line.

4. Variables: Variables are created by assigning a value to a name using the = operator. The name of the variable must follow certain rules, such as starting with a letter or underscore and consisting of letters, digits, and underscores.

5. Input and output: Python uses the input() function to read input from the user, and the print() function to display output to the screen.

Here's an example of a simple Python program that demonstrates some of these concepts:

In this program, the input() function is used to read the user's input, and the print() function is used to display a message on the screen. Then + the operator is used to concatenate the strings.

TYPES OF OPERATORS:-

In Python, several types of operators can be used to perform different kinds of operations. Here are some of the commonly used operator types:

1. Arithmetic Operators: Arithmetic operators are used to performing mathematical operations like addition, subtraction, multiplication, division, and modulus. Examples of arithmetic operators are +, -, *, /, and %.

2. Comparison Operators: Comparison operators are used to comparing two values and return a Boolean value (True or False). Examples of comparison operators are ==, !=, >, <, >=, and <=.

3. Logical Operators: Logical operators are used to combining multiple conditions and return a Boolean value (True or False). Examples of logical operators are and, or, and not.

4. Assignment Operators: Assignment operators are used to assigning a value to a variable. Examples of assignment operators are =, +=, -=, *=, /=, and %=.

5. Identity Operators: Identity operators are used to comparing the memory location of two objects. Examples of identity operators are is and is not.

6. Membership Operators: Membership operators are used to testing whether a value is present in a sequence or not. Examples of membership operators are in and not in.

7. Bitwise Operators: Bitwise operators are used to performing bitwise operations on integers. Examples of bitwise operators are &, |, ^, <<, and >>.

Using these operators, you can perform different kinds of operations in Python, such as arithmetic calculations, comparisons, and logical operations.

DECISION MAKING IN PYTHON:-

In Python, decision-making is done using conditional statements, which allow the program to perform different actions based on different conditions. The two main types of conditional statements in Python are the if statement and the if-else statement.

1. if statement: The if statement is used to check a single condition and execute a block of code if the condition is true. The basic syntax of the if statement is as follows:

2. if-else statement: The if-else statement is used to check a condition and execute a block of code if the condition is true, and another block of code if the condition is false. The basic syntax of the if-else statement is as follows:

3. if-elif-else statement: The if-elif-else statement is used to check multiple conditions and execute different blocks of code based on which condition is true. The basic syntax of the if-elif-else statement is as follows:

  STRINGS IN PYTHON:-

In Python, a string is a sequence of characters enclosed in quotation marks. Strings are a fundamental data type and are used to represent text in a program. Here are some common operations that can be performed on strings in Python:

1. Creating a string: To create a string in Python, you simply enclose a sequence of characters in either single or double quotes. For example:

2. Accessing characters in a string: You can access individual characters in a string using indexing. In Python, indexing starts from 0, so the first character in a string has an index of 0. For example:

3. Slicing a string: You can extract a substring from a string using slicing. Slicing allows you to extract a portion of a string by specifying the starting and ending indices. For example:

4. Concatenating strings: You can concatenate two or more strings together using the + operator. For example:

5. String methods: Python provides a variety of built-in string methods that allow you to manipulate and modify strings. Some common string methods include lower(), upper(), strip(), and replace(). For example:

Strings are a versatile and important data type in Python, and understanding how to work with them is essential for many programming tasks.

METHODS IN PYTHON:-

In Python, a method is a function that is associated with an object. Methods are used to perform operations on objects, and are called using dot notation. Here are some examples of common methods used in Python:

1. append(): This method is used to add an element to the end of a list. For example:

2. upper(): This method is used to convert a string to uppercase. For example:

3. split(): This method is used to split a string into a list of substrings based on a specified separator. For example:




4. join(): This method is used to join the elements of a list into a single string using a specified separator. For example:




5. sort(): This method is used to sort a list in ascending order. For example:

6. replace(): This method is used to replace all occurrences of a substring in a string with a specified replacement string. For example:

These are just a few examples of the many methods available in Python. Understanding how to use methods is an important part of working with Python objects and data types.