Computer Study

How to Setup Python Environment

Python is a high-level, interpreted, interactive, and object-oriented programming language. It is designed to be highly readable and easy to learn. Python uses English keywords frequently, which makes it more readable than other languages that use punctuation. It also has fewer syntactical constructions than other languages, making it easier to learn and use.

Python is interpreted, which means that it is processed at runtime by the interpreter. This makes it faster to develop and debug programs than compiled languages. Python is also interactive, which means that you can interact with the interpreter directly at a prompt. This makes it easy to experiment with code and learn the language.

Python is object-oriented, which means that it supports the development of programs by grouping related data and functions together into objects. This makes programs easier to read, understand, and maintain.

Python is a great language for beginners and experienced programmers alike. It is a powerful language that can be used to develop a wide range of applications, from simple text processing to complex web applications and games.

Here are some additional benefits of using Python:

  • It is free and open-source.
  • It has a large and active community of users and developers.
  • It is portable and can be used on a variety of platforms.
  • It is well-documented and has a large library of modules and tools.
  • It is easy to learn and use.

If you are looking for a powerful and versatile programming language, Python is a great choice.

History of Python

Python is a high-level, general-purpose programming language that was first created in the late 1980s by Guido van Rossum. Here is a brief history of Python:

– In 1989, Guido van Rossum, a Dutch programmer, started working on Python as a successor to the ABC programming language. The name “Python” was inspired by the British comedy group Monty Python.

– The first version of Python, version 0.9.0, was released in February 1991. It was a simple, interpreted language with support for data types such as lists, dictionaries, and strings.

– Python 1.0 was released in January 1994, with several new features, including support for modules, classes, and exceptions.

– Python 2.0 was released in October 2000, with many new features and improvements, including support for garbage collection, list comprehensions, and a full-fledged Unicode system.

– Python 3.0, a major revision of the language, was released in December 2008. It was designed to be backward-incompatible with Python 2.x to address some of the design issues in the earlier versions of the language.

– Since then, Python has become one of the most popular programming languages in the world, with a large and active community of developers and users.

– The latest stable release of Python is Python 3.10.0, which was released in October 2021, with several new features and improvements.

Python Features

Python’s popularity is due to its ease of use, readability, and versatility, making it a language of choice for a wide range of applications and industries.

Python is a popular and versatile programming language that has many distinctive features. Here are some of the key features of Python:

1. Simple and easy to learn: Python has a simple and intuitive syntax that makes it easy to learn and read. It uses English-like keywords, which makes it accessible even to beginners.

2. Interpreted: Python is an interpreted language, which means that it does not need to be compiled before execution. Instead, Python code is interpreted by the Python interpreter at runtime, which makes the development process faster and more efficient.

3. High-level: Python is a high-level language, which means that it abstracts away low-level details and provides more concise and readable code. This makes it easier to write and understand complex programs.

4. Dynamically typed: Python is a dynamically typed language, which means that data types are determined at runtime rather than at compile time. This makes it easier to write code that is flexible and adaptable to changing requirements.

5. Object-oriented: Python is an object-oriented language, which means that it supports the creation of objects and classes. This makes it easier to organize code into reusable and modular components.

6. Portable: Python is a portable language, which means that Python code can be run on any platform without modification. This makes it easier to write cross-platform applications and ensures that Python programs are highly compatible.

7. Large standard library: Python has a large and comprehensive standard library that includes many useful modules and functions for a variety of tasks, such as file I/O, network programming, and regular expressions.

8. Third-party modules: Python has a vast ecosystem of third-party modules and packages that extend its capabilities and make it suitable for a wide range of applications.

9. Easy to debug: Python provides a rich set of debugging tools, such as the built-in debugger and profiling tools, which make it easier to identify and fix errors in code.

10. Versatile: Python is a versatile language that can be used for a wide range of applications, including web development, data analysis, machine learning, scientific computing, game development, and automation.

These are just a few of the key features of Python that make it a popular and versatile language for a wide range of applications and industries.

 

How to set up our Python environment.

Setting up a Python environment involves installing Python on your computer and configuring it to work with your code editor or integrated development environment (IDE). Here are the basic steps to set up a Python environment:

1. Install Python: First, you need to download and install Python on your computer. You can download the latest version of Python from the official website (https://www.python.org/downloads/). Follow the instructions to install Python on your operating system.

2. Choose a code editor or IDE: Next, you need to choose a code editor or IDE to write and edit Python code. Some popular choices include Visual Studio Code, PyCharm, Sublime Text, Atom, and IDLE (which comes bundled with Python).

3. Set up a virtual environment: It is recommended to set up a virtual environment for your Python projects. A virtual environment is a separate environment for Python that allows you to install packages and libraries without affecting the system Python installation. To set up a virtual environment, you can use the `venv` module that comes with Python.

To create a virtual environment, open a terminal or command prompt, navigate to your project directory, and run the following command:

python -m venv env

This will create a new virtual environment in a directory named `env`.

4. Activate the virtual environment: Once you have created a virtual environment, you need to activate it. To activate the virtual environment, run the following command:

source env/bin/activate # on Linux and macOS
env\Scripts\activate.bat # on Windows

This will activate the virtual environment and set up your shell to use the Python version and packages installed in the environment.

5. Install packages: Finally, you can use the `pip` package manager to install any packages or libraries you need for your project. To install a package, run the following command:

pip install package-name

Replace `package-name` with the name of the package you want to install.

With these steps, you should now have a working Python environment set up on your computer. You can now start writing and running Python code in your code editor or IDE.

Getting Python

The most up-to-date and current source code, binaries, documentation, news, etc., is available on the official website of Python https://www.python.org/

You can download Python documentation from https://www.python.org/doc/. The documentation is available in HTML, PDF, and PostScript formats.

Installing Python

Python distribution is available for a wide variety of platforms. You need to download only the binary code applicable for your platform and install Python.

If the binary code for your platform is not available, you need a C compiler to compile the source code manually. Compiling the source code offers more flexibility in terms of choice of features that you require in your installation.

Here is a quick overview of installing Python on various platforms −

Unix and Linux Installation

Here are the simple steps to install Python on Unix/Linux machine.

  • Open a Web browser and go to https://www.python.org/downloads/.
  • Follow the link to download zipped source code available for Unix/Linux.
  • Download and extract files.
  • Editing the Modules/Setup file if you want to customize some options.

Now issue the following commands:

$ run ./configure script
$ make
$ make install

This installs Python at standard location /usr/local/bin and its libraries at /usr/local/lib/pythonXX where XX is the version of Python.

Using Yum Command

Red Hat Enterprise Linux (RHEL 8) does not install Python 3 by default. We usually use yum command on CentOS and other related variants. The procedure for installing Python-3 on RHEL 8 is as follows:

$ sudo yum install python3

Windows Installation

Here are the steps to install Python on Windows machine.

  • Open a Web browser and go to https://www.python.org/downloads/.
  • Follow the link for the Windows installer python-XYZ.msi file where XYZ is the version you need to install.
  • To use this installer python-XYZ.msi, the Windows system must support Microsoft Installer 2.0. Save the installer file to your local machine and then run it to find out if your machine supports MSI.
  • Run the downloaded file. This brings up the Python install wizard, which is really easy to use. Just accept the default settings, wait until the install is finished, and you are done.

Macintosh Installation

Recent Macs come with Python installed, but it may be several years out of date. See http://www.python.org/download/mac/ for instructions on getting the current version along with extra tools to support development on the Mac. For older Mac OS’s before Mac OS X 10.3 (released in 2003), MacPython is available.

Jack Jansen maintains it and you can have full access to the entire documentation at his website − http://www.cwi.nl/~jack/macpython.html. You can find complete installation details for Mac OS installation.

Setting up PATH

Programs and other executable files can be in many directories, so operating systems provide a search path that lists the directories that the OS searches for executables.

The path is stored in an environment variable, which is a named string maintained by the operating system. This variable contains information available to the command shell and other programs.

The path variable is named as PATH in Unix or Path in Windows (Unix is case sensitive; Windows is not).

In Mac OS, the installer handles the path details. To invoke the Python interpreter from any particular directory, you must add the Python directory to your path.

Setting path at Unix/Linux

To add the Python directory to the path for a particular session in Unix −

  • In the csh shell − type setenv PATH “$PATH:/usr/local/bin/python” and press Enter.
  • In the bash shell (Linux) − type export PATH=”$PATH:/usr/local/bin/python” and press Enter.
  • In the sh or ksh shell − type PATH=”$PATH:/usr/local/bin/python” and press Enter.
  • Note − /usr/local/bin/python is the path of the Python directory

Setting path at Windows

To add the Python directory to the path for a particular session in Windows −

At the command prompt − type path %path%;C:\Python and press Enter.

Note − C:\Python is the path of the Python directory

Python Environment Variables

Here are important environment variables, which can be recognized by Python −

Sr.No. Variable & Description
1 PYTHONPATH

It has a role similar to PATH. This variable tells the Python interpreter where to locate the module files imported into a program. It should include the Python source library directory and the directories containing Python source code. PYTHONPATH is sometimes preset by the Python installer.

2 PYTHONSTARTUP

It contains the path of an initialization file containing Python source code. It is executed every time you start the interpreter. It is named as .pythonrc.py in Unix and it contains commands that load utilities or modify PYTHONPATH.

3 PYTHONCASEOK

It is used in Windows to instruct Python to find the first case-insensitive match in an import statement. Set this variable to any value to activate it.

4 PYTHONHOME

It is an alternative module search path. It is usually embedded in the PYTHONSTARTUP or PYTHONPATH directories to make switching module libraries easy.

Running Python

There are three different ways to start Python −

Interactive Interpreter

You can start Python from Unix, DOS, or any other system that provides you a command-line interpreter or shell window.

Enter python the command line.

Start coding right away in the interactive interpreter.

$python # Unix/Linux
or
python% # Unix/Linux
or
C:> python # Windows/DOS

Here is the list of all the available command line options −

Sr.No. Option & Description
1 -d

It provides debug output.

2 -O

It generates optimized bytecode (resulting in .pyo files).

3 -S

Do not run import site to look for Python paths on startup.

4 -v

verbose output (detailed trace on import statements).

5 -X

disable class-based built-in exceptions (just use strings); obsolete starting with version 1.6.

6 -c cmd

run Python script sent in as cmd string

7 file

run Python script from given file

Script from the Command-line

A Python script can be executed at command line by invoking the interpreter on your application, as in the following −

$python script.py # Unix/Linux

or

python% script.py # Unix/Linux

or

C: >python script.py # Windows/DOS

Note − Be sure the file permission mode allows execution.

Integrated Development Environment

You can run Python from a Graphical User Interface (GUI) environment as well, if you have a GUI application on your system that supports Python.

  • Unix − IDLE is the very first Unix IDE for Python.
  • Windows − PythonWin is the first Windows interface for Python and is an IDE with a GUI.
  • Macintosh − The Macintosh version of Python along with the IDLE IDE is available from the main website, downloadable as either MacBinary or BinHex’d files.

If you are not able to set up the environment properly, then you can take help from your system admin. Make sure the Python environment is properly set up and working perfectly fine.

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