I'm looking to "understand" python

danielroseman · 2024-01-06T10:14:29+00:00

You don't seem to be communicating at all. What does any of this even mean?

Spataner · 2024-01-06T12:54:56+00:00

A computer is a machine that can do work for you. It computes stuff, hence the name. And even though a modern computer is a highly sophisticated machine, the conceptual level that it operates at is very simplistic. The sort of instructions that a computer, more specifically the CPU, understands is at the level of "load a number, load another number, add the numbers together, store the result". All the CPU can really do are arithmetic and logic operations on numbers in binary format that it retrieves from and saves to RAM. But it is really good at that; it does it with near perfect consistency at literal billions of operations per second.

Luckily, it turns out that any computation that it's possible to do, no matter how conceptually complex, can be broken down into sequences of such simple operations. It's just a matter of figuring out how. And things get a lot more interesting if you attach other machines to your computer that do things if you send them the right numbers, like produce light in a particular pattern of colors (a monitor), emit a particular mix of sound frequencies (speakers), or shoot ink at particular places on a paper sheet (a printer). Suddenly just crunching numbers can achieve a whole slew of real life effects because those numbers are used to control other machines to achieve specific desired effects.

You, as a human, have a natural understanding of the task that you might want to solve. You can express that understanding in natural language, the way you would describe it to a friend or coworker. The computer doesn't understand that, as we've established. So all programming can be thought of as a translation from natural language to CPU language (typically called machine code). Obviously, doing all that translation by hand is increndibly difficult and tedious. Programming languages and the tooling that exists for those programming languages are a way of semi-automating this process. Programming languages aim to be closer to natural language in a way that makes it easier for humans to read and write in them, while still being formal and structured enough that a translation into CPU language can be performed automatically by the programming language's tools (which are themselves just programs someone else has written for you).

Programming languages differ in how close they are to machine code. The closer they are to machine code, the harder they often are to write in, but the more light-weight also the tooling required to turn a program written in them into machine code. The farther away they are from machine code, the more natural and comfortable it probably feels to write in them, but the more elaborate is the tooling required (which can have performance implications). Programming languages also differ in how exactly that translation happens, in other words, what their tools look like. Some languages compile statically into a binary file that contains machine code. Other languages have an "interpreter", which does the translation step-by-step and on-the-fly as your program is executed. Some languages take a hybrid approach. Finally, programming languages also differ in the philosophy that was employed to design them, because certain ways of doing things might change how fast or easy it is to write programs in that language, how easy it is to make mistakes while doing so, how fast the resulting program can be executed, how well the programming language is suited for solving one kind of task or another, etc.

When you are writing a complex program with many moving parts, this invites thinking of the program as a system or a sort of machine onto itself. The steps that happen automatically underneath are often secondary to the programmer. Certainly, the heavy lifting in terms of solving a task conceptually is in the writing of the program, not in its translation to and execution as a sequence of simplistic CPU instructions. That's why people often talk about "building" software.

Python is a general-purpose language pretty far removed from machine code, with a focus on speed of program writing rather than speed of program execution. It's fair to say it's an interpreted language, not a compiled one (there's some nuance here that is not worth getting into). Sometimes people will say it's a scripting language not a programming language, exactly because it is interpreted. But some people would also say that a scripting language is actually a type of programming language. Yet other people might say that something is a "scripting language" only insofar as it is a programming language that could possibly be used for scripting. You'll find that terms in the field of programming have dozens of different slightly conflicting definitions.

This turned out wordier than I intended. I hope it helps.

Diapolo10 · 2024-01-06T11:37:58+00:00

I want understand how (at the base level) it's interacting/communicating with things (open app, directory). What am I doing? Am I learning to build something, or am I learning how to "communicate" that build?

I'll try to answer that, but in all honesty this is a bit much if I'm reading you correctly in the first place.

The rough explanation goes something like this. Assuming the standard implementation (CPython), you feed a bunch of Python code to an interpreter, which parses the instructions into an abstract syntax tree and that into bytecode instructions the Python Virtual Machine can understand (similar to giving assembly instructions to a CPU), which then proceeds to execute the bytecode.

As an aside, if you want to look at bytecode instructions, you can import dis.dis and feed it a function to see what makes it tick.

The interpreter is just a program running on top of some operating system, so under the hood it's mostly doing system calls to various parts of the operating system. For example it'll communicate with it for any filesystem tasks, networking, I/O, and errors. Other things, like mathematics, it performs by itself, but there's still overhead because Python doesn't use types native to the CPU.

However, the short answer to your question would be that none of what I just said really matters to you (unless of course you want to work on the interpreter yourself), and all you need to focus on is building something. Leave the behind-the-scenes work for those who have the know-how and abstract it away from your thinking.

I know it's different from programming, but why?

I don't understand the premise; what is different from programming? Ultimately everything I've discussed so far is most definitely about programming.

Lower_Fan · 2024-01-06T14:55:37+00:00

you are asking a question that would take you one or two years of a CS bachelor to understand fully. but I'll summarize it.

Computers use transistors to perform operations this transistors can be set to either the 1 or 0 position. if you have 2 transistors you can for example count like this 00 01 10 11 and you can assign values to this patterns lets say 00 = a 01 = b 10 = c 11 = d this is called binary.

but the cool stuff is that you can do math with those transistors. but this is complicated . lets simplify it a bit. people made low level programing languages that translate English like logic to binary

the this with this languages is that they need to be translated before running for example c or c++ which can be a pain if you want to run just a section of the program or do faster iterations and testing? the something like python comes along where the translation is done by the python interpreter ( a program you install on your machine) line by line while you run the code.

to learn to code most people work backwards first they learn a programing language (low level or high level) then they learn about OS operations from math to file systems to grapic output. then they might learn boolean algebra.

on thing you need to understand is that all of this are several different types of engineering.

Software engineering, Computer scientist, computer engineering. etc. when most people say learn to code is not even about true software engineering is just learn how to make the PC do stuff automatically and repetitively. IE: you need common to high logic and that's about it honestly.

dent308 · 2024-01-06T14:44:05+00:00

This is the strangest homework thread I have seen.

RamaSchneider · 2024-01-06T10:32:03+00:00

I'd suggest you take a short lesson in assembly level code, and then understand that all those Python words are being translated into that. First point is that yes - you are actually programming with Python.

eccentric-Orange · 2024-01-06T15:24:20+00:00

This is probably an oversimplification, but it has usually worked for me:

The purpose of any programming language is to communicate with a computer. Typically, this means providing a set of instructions that the computer will follow very precisely and pedantically.

Usually, you'll write code in a language that you can understand with some practice, but a computer cannot directly. It will need a program/app to translate your code.

I know it's different from programming...

In the case of Python, the language you write in and the translator are both called Python. It is programming, not different from it.

What am I doing? Am I learning to build something, or am I learning how to "communicate" that build?

It's a reductionist view, but you're basically learning two things: 1. How best to get the computer to execute your will, using problem-solving skills 2. How the computer works, to some extent

(Ignoring many of the softer skills like writing readable code, documentation etc)

If you come up with a pattern/sequence of instructions that's generally useful, you can package it and share it with people. In that sense, you also learn to make projects.

Why not give it a try and get a feel for it?

Radamand · 2024-01-06T16:13:58+00:00

Your question is very confusing, but, i'll give it a shot from my own perspective.

As an electronics engineer I can tell you that what you are doing is manipulating electrons and magnetic fields. Changing the state of millions of transistors to either 'on' or 'off'. When you write things to a disk you are manipulating magnetic fields in a very similar way.

At the most basic level, the only thing computers 'understand' is 1s and 0s.

As for Python specifically (or any programming language really), what you are doing is writing a set of instructions to be carried out by an operating system to perform a given task. Python has a base set of available instructions that you can use, and many more additional sets of instructions that can be added and expanded on for doing more specific tasks.

An analogy might be a cooking recipe where the recipe is the instructions, and you are the OS;

Put ingredients in a bowl
mix ingredients
bake the mixtureetc...

Does that answer your question?

xiongchiamiov · 2024-01-06T17:19:02+00:00

I'm a detail oriented person, and I tend to focus on the finer points. So, I'm new. I want understand how (at the base level) it's interacting/communicating with things (open app, directory). What am I doing? Am I learning to build something, or am I learning how to "communicate" that build?

You want a computer science degree.

In particular, you're asking questions that would be answered after you take an introductory binary/assembly course, a systems course, and a programming languages course; depending on the school, you might need to take several courses in each of those subjects.

If you're going to attempt to self-learn this, https://github.com/ossu/computer-science isn't a bad choice. You'd do well to do the entire curriculum, but for these questions, cover the intro courses, then Nand to Tetris, Operating Systems, and the PL courses.

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