Python is an interpreted language developed by Guido van Rossum in the year of 1991. As we all know Python is one of the most high-level languages used today because of its massive versatility and portable library & framework features. It is an interpreted language because it executes line-by-line instructions. There are actually two way to execute python code one is in Interactive mode and another thing is having Python prompts which is also called script mode. Python does not convert high level code into low level code as many other programming languages do rather it will scan the entire code into something called bytecode. every time when Python developer runs the code and start to execute the compilation part execute first and then it generate an byte code which get converted by PVM Python Virtual machine that understand the analogy and give the desired output

1. Introducing the Python
Interpreter
The Python interpreter is the core component that executes Python
code, whether in interactive mode or through script files. It provides a
powerful and flexible platform for developers to write, test, and run
their programs.
SS
by Shashikant Sathe

2. Starting the Python
Interpreter
1 Interactive Mode
The Python interpreter can
be started in interactive
mode, allowing you to
execute commands and see
immediate results.
2 Script Execution
Python programs can also
be saved as script files and
executed directly by the
interpreter.
3 Command Line
The interpreter can be launched from the command line,
providing a quick and convenient way to start coding.

3. Executing Python Programs
Interactive Execution
In interactive mode, each statement
is executed immediately, and the
results are displayed on the console.
Script Execution
When running a Python script, the
interpreter executes the entire
program from start to finish,
producing the final output.
Debugging
The interpreter provides tools and
features to help developers debug
their code, such as breakpoints and
step-by-step execution.

4. Interactive vs. Script
Execution
Interactive Mode
Ideal for quick testing,
experimenting, and exploring
the language. Allows
immediate feedback and
exploration.
Script Execution
Better for developing and
running larger, more complex
programs. Scripts can be
easily shared, version
controlled, and executed
repeatedly.
Combination
Developers often use a combination of interactive mode and script
execution, depending on the task at hand.

5. The Execution Model
1
Source Code
Python code is written in the .py file format, containing high-level,
human-readable statements.
2
Bytecode Generation
The interpreter converts the source code into a lower-level,
machine-readable bytecode representation.
3
Execution
The interpreter then executes the bytecode, performing the
instructions and producing the final output.

6. The Python Interpreter Workflow
Input
The interpreter receives the Python code, either from an interactive
session or a script file.
Parsing
The code is parsed and validated, ensuring it follows the Python syntax
rules.
Bytecode Generation
The validated code is then transformed into a lower-level bytecode
representation.
Execution
The bytecode is executed by the interpreter, which performs the
necessary operations and produces the output.

7. Interpretation vs. Compilation
Interpreted Languages
Python is an interpreted language,
where the interpreter executes the
code line by line, without a separate
compilation step.
Compiled Languages
Compiled languages, such as C or
Java, go through a separate
compilation step to generate
machine-executable code.
Differences
Interpreted languages are generally
more flexible and easier to use, while
compiled languages can offer better
performance.

8. Execution Model Variations
CPython The standard Python implementation, which uses an
interpreter to execute the bytecode.
Jython A Python implementation that runs on the Java Virtual
Machine (JVM).
PyPy A Python implementation that uses just-in-time (JIT)
compilation for improved performance.

9. Just-In-Time (JIT) Compilation
1 Source Code
The Python source code is first converted to bytecode, just like
in the standard interpreter.
2 JIT Compilation
The JIT compiler analyzes the bytecode and generates
optimized machine code on-the-fly.
3 Execution
The optimized machine code is then executed, providing a
significant performance boost over the standard interpreter.

10. Conclusion: Python's
Execution Options
1 Flexibility
Python offers a variety of
execution models, allowing
developers to choose the
one that best fits their
needs.
2 Performance
Innovations like JIT
compilation can
significantly improve the
performance of Python
programs.
3 Ecosystem
The Python community has developed a rich ecosystem of tools
and implementations to enhance the language's capabilities.