A Python Implementation Comparison

Python is amazing.

Surprisingly, that’s a fairly ambiguous statement. What do I mean by ‘Python’? Do I mean Python the abstractinterface? Do I mean CPython, the common Python implementation (and not to be confused with the similarly named Cython)? Or do I mean something else entirely? Maybe I’m obliquely referring to Jython, or IronPython, or PyPy. Or maybe I’ve really gone off the deep end and I’m talking about RPython or RubyPython (which are very, very different things).

While the technologies mentioned above are commonly-named and commonly-referenced, some of them serve completely different purposes (or, at least, operate in completely different ways).

Throughout my time working with the Python interfaces, I’ve run across tons of these .*ython tools. But not until recently did I take the time to understand what they are, how they work, and why they’re necessary (in their own ways).

In this tutorial, I’ll start from scratch and move through the various Python implementations, concluding with a thorough introduction to PyPy, which I believe is the future of the language.

It all starts with an understanding of what ‘Python’ actually is.

If you have a good understanding for machine code, virtual machines, and the like, feel free to skip ahead.

“Is Python interpreted or compiled?”

This is a common point of confusion for Python beginners.

The first thing to realize when making a comparison is that ‘Python’ is an interface. There’s a specification of what Python should do and how it should behave (as with any interface). And there are multipleimplementations (as with any interface).

The second thing to realize is that ‘interpreted’ and ‘compiled’ are properties of an implementation, not aninterface.

So the question itself isn’t really well-formed.

Is Python interpreted or compiled? The question isn’t really well-formed.

That said, for the most common Python implementation (CPython: written in C, often referred to as simply ‘Python’, and surely what you’re using if you have no idea what I’m talking about), the answer is: interpreted, with some compilation. CPython compiles* Python source code to bytecode, and then interprets this bytecode, executing it as it goes.

* Note: this isn’t ‘compilation’ in the traditional sense of the word. Typically, we’d say that ‘compilation’ is taking a high-level language and converting it to machine code. But it is a ‘compilation’ of sorts.

Let’s look at that answer more closely, as it will help us understand some of the concepts that come up later in the post.

Bytecode vs. Machine Code

It’s very important to understand the difference between bytecode vs. machine code (aka native code), perhaps best illustrated by example:

  • C compiles to machine code, which is then run directly on your processor. Each instruction instructs your CPU to move stuff around.
  • Java compiles to bytecode, which is then run on the Java Virtual Machine (JVM), an abstraction of a computer that executes programs. Each instruction is then handled by the JVM, which interacts with your computer.

In very brief terms: machine code is much faster, but ……continue reading…..

 

 

Thank you for reading my blog , the reference is taken from one of the article that was published by Charles Marsh on Toptal. Please feel free to leave me some feedback or to suggest any future topics.

Looking forward to hear from you – Swadhin Ray (Sloba) -( LinkedIn ) ( Twitter )

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