How to Run a Python Script?

The historical blur between scripting languages and general-purpose programming languages has caused Python to be considered a scripting language by a large audience. The python script is a file containing the commands that are structured to be executed like a program. But how do you run it? What do we exactly mean by running a Python Script? Let us find out the answers of all of these questions with the help of this blog about Python Script.

1. What is Python Script
2. How can a Python program be executed?
3. Need for scripting 
4. Advantages of Scripting
5. Python and Java
6. How to write Python Scripts?
7. Need for Documenting the Code
8. How to reload modules
9. Converting the Python Script into .exe file
10. What is the difference between Code, Script and Modules?

What is Python Script?

A Python script, the file containing the commands, is structured to be executed like a program. These files are designed to contain various functions and import various modules. Python interactive shell or the respective command line is used to execute the script, to perform a specific task. A script is structured by defining the set of function definitions and then stating the main program used to call the functions.

A program consists of numerous tasks; these tasks can be executed with the help of scripts. Unlike libraries, scripts can be used without importing and are less code-intensive.

How can a Python program be executed?

The different ways in which a python program can be executed successfully are:

1. By the Python Terminal. Interactive mode for programming is used to develop new solutions from scratch and execute them in state-of-the-art ways.
2. By implementing Scripting.

Need for scripting 

The development of complicated programs using the python terminal is very difficult, complex, and time-consuming. Scripting is used for the development of such complex and large programs. 

Windows Users:

The steps for the methods are first, writing the python program in notepad second, saving the program saved using a .py extension, and finally, executing the respective program by typing the name of the program in the command prompt “python filename.py”.

Note: Set the path variable correctly before executing the script.

Mac Users:

Double-click the script in the Finder, to run a script application. The events and results can’t be viewed if running a script app outside of Script Editor.

Advantages of Scripting

Scripting, developing a set of commands designed to work together, to execute a needed task or set of tasks.

The demand for scripting languages increases as there is a need for easy solutions for developing complex programs in the market. As the popularity and the traction for these scripting languages increase, developers try to push the limits to get faster and better results. They are easy to develop and can be executed in a short time. 

Note: Python is still considered to have the upper hand, and scripts can mostly be used for integrations-related tasks. Developers should know the boundaries and should respect them.

Python and Java

Python Scripts are nothing but the codes that are written in the python programs.  

Like Java, Python has its PVM (Python Virtual Machine). The PVM can convert the script into byte code. The .pyc files in python, also known as compiled python files, use a similar architecture for execution. In python, the process is done to modules for better performance during the execution. 

Python states:

Python language is interpreted in nature. Due to the presence of the bytecode compiler, the distinction between interpreted or compiled are almost blurry. There is no need to create an executable file to run, as the source files can be run directly.

The architecture of the program is different from a solid script. It is complex and diverse.

How to write Python Scripts?

The script in python and the shell script are almost the same things. They both are lines of python code written in a plain text file; these python codes are designed as solutions that are executed systematically. 

A text editor with syntax highlighting is essential. Developers can easily create and edit a Python script using a good text editor.

The most versatile text editor currently available in the market is VSCode, provided by Microsoft. 

Windows Users:

Can install and run it directly or through Anaconda

Mac Users:

Can install and run it through Anaconda.

Need for Documenting the Code

Documenting the written python code is very important. It helps in easy usage of the code for others and also for yourself. With proper documentation, the structuring and usage of the respective code can be easily remembered for future purposes. For documenting a source code, we make use of comments. Comments are denoted by #. Python ignores the text written as comments.

Note:

• Plain text files can be used to create and store Python commands 
• Use python <scriptname> to run the respective file
• Extension .py is generally used for python scripts.
• Always opt for a syntax-highlighting text editor to edit your Python scripts.
• Make use of comments, as the comments improve the readability of your code and can be used to understand the structuring and usage of the script for future purposes.

How to reload modules

A Python module is a set of parameters and functions together in a single .py file. They are files implemented in need of pre-defined functions.

While importing a module, Python secures the commands for importing the respective module. If another statement makes the command for importing the same module, Python automatically neglects the command. The folder sys. modules contain the list of modules already loaded. Loading the same module can be time-consuming. 

For force reloading of a module, while debugging a script using a .exe file or running the program from an IPython shell, we have to use the reload command. Otherwise, the changes that were made in the script will not be refreshed after re-executing the script.

Converting the Python Script into .exe file

With the help of the .exe file, the program developed can be run on a system without the need for an IDE shell. 

Step 1: Use the command: pip install pyinstaller, type it in the command prompt 

Step 2: Open the directory where the respective .py file is located. 

Step 3: Open the Power shell window by clicking the Right button and simultaneously pressing the shift button.

Step 4: Use the command: pyinstaller –onefile -w ‘filename.py’, type it in the command prompt 

Step 5: After executing the command, go to the new-made directory, open the dist folder for the exe.file

What is the difference between Code, Script, and Modules?

Code	Script	Modules
Code is a group of instructions written in any programmer’s preferred coding language, for example, C, C++, Java, Python, etc. A compiler or interpreter must make the computer understand the meaning and execute them successfully.	The script is a set of instructions that the computer understands without the help of a compiler or interpreter to perform certain assigned tasks.	Modules are the most independently workable set of computer instructions mostly used to integrate one device with another, with modules containing certain code that is portable, compatible, and efficient. Once developed can be integrated with small changes or no change.
Ex: Normal stage 1 source code any programmer will write	Ex: JavaScript, Perl, etc.	Ex: ERP with many modules like attendance, Leaves, etc. These can be incorporated at any company’s end with minimal or no change.

The Python Interpreter: 

Python is a line-by-line interpreter, which means it runs code line by line. As we all know, computers cannot understand our language and can only understand machine language, commonly known as binary. As a result, the Python interpreter converts user-written Python code into a language that can be understood by computer hardware or systems. Every time you run your Python script, this happens.

The python code can be created in any text editor and saved on our system with the “.py” extension. So, what’s the deal with this code? Some programmes or software, such as “python” or “python3,” must be installed on your computer, and it is up to them to run the python code. This type of software is known as an interpreter.

Python does include a number of useful features.

Because the Python interpreter receives the command first, then evaluates it, outputs the results, and then loops back to read the command, only Python is referred to as REPL (Read, Evaluate, Print, Loop).

Visit this link to download Python’s latest version

Starting the Python Interpreter

To get started with Python interpretation, you’ll need to download and install the newest Python software, which is free and open-source. We can use the Python interpreter after the installation is complete. How do we get started? This is the question that arises. So, in response to that query, we have a number of options for getting started with Python interpretation at your leisure. For successful coding, you can choose from the options below.

Method 1: Use a regular notepad to write code, save it with a.py extension, then run it by dragging the file into Python’s built-in command prompt, which we call Python Shell /RELP.

Method 2: Use the Python IDE, which is a piece of software that assists you in creating and executing code files.

Method 3: Use online Python interpreters or work environments such as Google Colab or other Python IDEs.

Method 4: Other open-source, free IDE options for Python code interpretation include Anaconda, Jupyter Notebook, Spyder, and others.

Running Python Code Interactively

In order to run the code iteratively, we have an option to use Python SHELL/RELP. This helps us to run code interactively in a sense it will accept the code line by line and give immediate output on the next line. 

Steps to start with Python SHELL

To use the Python Shell, type python into the command prompt or power shell on Windows or the terminal window on Mac >> >>> appears a Python Prompt with three greater-than symbols >>> You can now get the result with just one sentence. Enter a basic phrase like 7 – 2 and hit enter; the result will appear on the next line, as seen below.

How to Run Python Script by the Interpreter?

The steps to accomplish so are as follows:

• The interpreter first processes your script’s statements or expressions in sequential order.
• The code is then turned into bytecode, which is a type of instruction set.
• The code is transformed into bytecode, which is a low-level language. It is a machine-independent intermediate code that optimizes the code execution process. As a result, when the interpreter runs the code again, it skips through the compilation stage.

Finally, the interpreter sends the code to the processor for execution. The Python Virtual Machine (PVM) is the final phase in the Python interpreter. It is a component of the Python environment that you have installed on your computer. In the Python runtime, the PVM loads the bytecode, reads each operation and executes it.

How to Run Python Script using Command-Line?

The most popular method is using a plain text editor to write a Python program. The code written in a Python interactive session is lost once it is closed, although it allows the user to write many lines of code. The files have an a.py extension on Windows.

If you’re just getting started with Python, you can use simple text editors like Sublime or Notepad++, or any other text editor.

Then you simply press the ENTER key on your keyboard. On the screen, you can see the phrase Hello World! Congrats! You’ve just finished running your first Python script.

If you do not receive the output, you should verify your system PATH and the location where you saved your file. If it still doesn’t work, try reinstalling Python on your PC.

How to Run Python Scripts From an IDE or a Text Editor

In addition to the essential tools, an Integrated Development Environment (IDE) is an application that allows a developer to build software within an integrated environment.

To write, debug, change, and run your modules and scripts, you can use the Python IDLE, a basic IDE included with the standard Python Distribution. Other IDEs that allow you to run your scripts inside their environment include Spyder, PyCharm, Eclipse, and Jupyter Notebook.

Python scripts can also be run in popular text editors like Sublime and Atom.

You must first create a project before you can run a Python script from your IDE or text editor. You can either add your.py file to it once it’s been generated, or you can just make one.

How to Run Python Scripts From a File Manager

In a file manager, you must double-click on the file icon to launch your Python script. This option is primarily utilized in the production stage once the source code has been released.

However, various criteria must be followed in order to achieve this:

You must save your script file with the extension.py for python.exe and .pyw for pythonw.exe on Windows in order to start it by double-clicking on it.

If you’re executing your script from the command line, you’ll almost certainly encounter a circumstance where a black window flashes over the screen. Include the statement input(‘Enter’) at the end of the script to avoid this. When you press the ENTER key, the software will exit. It’s worth noting that the input() function will only operate if your code is error-free.

• Your Python script must include the hashbang line and execution permissions on GNU/Linux and other Unix-like systems. In a file manager, the double-click method will not function otherwise.

Though it is simple to run a script by double-clicking on it, it isn’t considered a viable method due to its limits and dependencies, such as the operating system, file manager, execution rights, and file associations.

As a result, this option should only be used after the code has been debugged and is suitable for production.

This brings us to the end of the blog on How to Run a Python Script. We hope that you have understood the concept comprehensively. To learn more about such concepts, join Great Learning’s PGP Artificial Intelligence and Machine Learning Course and upskill today. The PGP- AIML Course offered Online Mentorship and Career Support to help you power ahead in your career.

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