Notes # 1 — Installing Python on Mac

At my work I recently started working on a project with a lot of Python and C++ in it. I have never worked on Python before, so I started learning it. I liked it a lot. It allows you write code a bit like Scala (which is another language I like).

So I thought recording my learning here on blog. Just to read them again if needed.

In this post I am writing about how I set up Python dev env on my personal Mac Mini.

Mac OS has oldPython pre installed.

I bought my mac mini some 18 months back. At that time I used to work on Scala (for work and personal projects). Afterwards at my new job, I moved away from Scala and started working on C++ Python etc.

So when I decided to get a python dev env on my Mac mini, I checked it. I found out that Mac OS comes with Python pre installed, but it is an old version. You wont use it for development.

➜  ~ which python
/usr/bin/python
➜  ~ python --version
Python 2.7.18

I didnt want to mess with this installed version.I never installed it and if it is preinstalled, I thought it will be for some reason. Later I figured out that this version of python is needed by the operating system as a dependency for some pre installed software packages. So I left it as it is.

Brew or Pip

When I decided to install a 3.x version of python, I realized that it can be installed using brew or Pip. I guess both should work, but I chose brew. Primarily because I am familiar with it and it is specific/exclusive to Mac OS.

So I did

brew install python3

which failed with, following error

cannot be installed as binary package and must be built from source.
Install the Command Line Tools:
xcode-select — install

This was self explaining, as Brew formulae needs a compiler or some command line tool, xcode-select bring most of it. I think sometime you may need full XCode, but I havent come across that situation yet.

Post xcode select installation, I was able to do brew python2 install successfully.

Two versions

Now I have two versions of python on my box.

➜  ~ python --version
Python 2.7.18
➜  ~ python3 --version
Python 3.8.9
➜  ~ which python3
/usr/bin/python3

I always wanted to use python3, so I defined an alias in my .zshrc

alias python=/usr/bin/python3

I restarted my session, and I do have python3 as my default

➜  ~ python --version
Python 3.8.9

Now I got python interpreter working

➜  ~ python
Python 3.8.9 (default, Jul 19 2021, 09:37:32)
[Clang 13.0.0 (clang-1300.0.27.3)] on darwin
Type "help", "copyright", "credits" or "license" for more information.
>>> print("hello")
hello

Python IDE

I didnt researched much on this. I has VSCode installed on my box, so I installed python extention.

This extension doesnt work out of the box, it requires two steps.

• It requires you to install python. (we already completed that step we completed)
• It requires you to manually select python interpreter. You need to make sure you choose the right version (i.e. 3.x)

With this you are ready to go.

Launch IDE & Run some code

Add following to you .zshrc

export PATH=$PATH:/Applications/Visual\ Studio\ Code.app/Contents/Resources/app/bin

Now you can launch IDE like this using code command

➜  ~ cd PythonTestCode
➜  PythonTestCode code .
➜  PythonTestCode code .

Now add some code and try to run it

You should see something like this in terminal window in IDE (usually at bootom)

➜  PythonTestCode /usr/bin/python3 /Users/vikrantsingh/PythonTestCode/first_file.py
Hello World!
➜  PythonTestCode

You can also debug it

Which will give you usual debug control on IDE

This setup up worked well for me till now. I am sure I will face some challenge if I go advance, but I do not think thats happening on this setup very soon.

Thanks for reading.