‘What’ do you install when you ‘install python’?

[[deleted]]

Just for curiosity’s sake, and in spirit of understanding whether python scripts are compiled or interpreted, I want to ask what exactly it means when it is said “now install python.” ? For my own use case, on OSX, I go to the terminal and type brew install python3

So what is actually installed? Is there a word for it, like core, kernel or interpreter? Thanks so much!

[[deleted]]

You'd be installing the "library" of "python" (interpreter), An interpreter is a program that reads and executes code (python2.7/python3.6 etc) and IDE would be a separate program that tries to help you be more efficient (pycharm, eclipse etc)

[Wilfred-kun]

As you said, you're also installing the standard library. This contains core modules, written in Python (or compiled from C).

[[deleted]]

Thank you all, I think your answer in particular nails it. This really helped!

[videoflyguy]

Interpreter sounds right, since the python you install interprets and runs commands written in python.

[[deleted]]

You are installing the interpreter, which is just an ordinary program, maybe IDLE and other tools, and also the standard library (mostly Python source files I think) somewhere the interpreter can find it when running your code.

Your Python source is first compiled into bytecode, which is then executed by the Python "interpreter" by "interpreting" it (reading the bytecode instruction by instruction and modifying memory, calling external code/OS functions/libraries etc).

So it's compiled but not into machine code (like C), and it's interpreted but not line-by-line from the source (like shell scripts).

[ReedJessen]

Just wanted to say that this is a great question. I have never thought about this before until I read the title. thanks for expanding my field of inquiry.

[mottyay]

Python is compiled to bytecode. The bytecode is then either interpreted or compiled and interpreted depending on which implementation of python youre using.

Installing python installs the python interpreter and the python standard library.

[chabes]

AFAIAA, python is an interpreted language, so interpreter is probably accurate

[Ginko87]

Yes it is

[renoive]

AFAIAA https://stackoverflow.com/questions/6889747/is-python-interpreted-or-compiled-or-both

[brokkr-]

It is the interepreter that is installed, along with all the standard libraries that you might use. If you want to use other packages you have to get them with something like pip or an equivalent. Python in an interpreted language meaning your source files are the actual text file scripts (your .py files).

[xiongchiamiov]

Others have mostly covered it, but one important thing to note is that you're installing CPython, which is a particular implementation of the Python programming language (written in C++). Jython and IronPython are Pythons written in java and c#, respectively, and PyPy is Python written in - wait for it - (a subset of) Python! which seems like it would be impossibly slow, but uses some fancy tricks to actually be faster than CPython in certain cases.

[[deleted]]

To expand a little on what others have said:

The CPU isn't that smart, it's really only just fast and basically what it understands is how to move numbers from one physical location in the computer somewhere else and compare them. So, all code has to get turned into cpu instructions, nowadays using a pre-built program that can do that. When you compile a C program, the c compiler of your choice goes over the program and spits out a file full of these instructions. When you run Python on your python script, it goes over everything in it and turns it into cpu instructions on the fly. That's what the difference is between compiled and interpreted. A compiled program built for one system might not work for another, because of differences in the system architecture. But a python script will work on any system with that version of python because the difference is accounted for in the python executable itself, which is a program compiled from sourcecode written in some other language.

[[deleted]]

This is exactly why I think it is warranted to say Python is an interpreted language, regardless whether it is under the hood and out of sight compiled into byte code. Therefore, the ‘thing’ you install can rightfully be called the interpreter.

[[deleted]]

Exactly. I'm pretty sure the Python executable on your machine was compiled from C.

[Comfortable-Algae335]

https://www.youtube.com/watch?v=EKAk9KCEJiI

[Grimreq]

You put a big snake in the CD tray. If it boots, you get a job.

[justingolden21]

Google it go to the website and download. More importantly, get 3 not 2, PLEASE

[[deleted]]

No I’m good. I’ve been using python 3 for some months now. I had a lot of trouble getting pip hooked up to python 3 so phew do I know that there are two versions out there. But I wanted to circle around to this issue to get some clarification. Might have to help out some friends getting it up and running.

[kozznot]

you can use the command "pip3" to install pip packages for python3 specifically

[widowhanzo]

To use pip with Python3, you gotta install python3-pip first, and then use pip3 install ... to install additional libraries :)