Computational Methods of Code Societies

Day 2 ~ taught by Melanie Hoffman and Nabil Hassein on January 8th 2019

🍃The computer, the programmer, the relationship they have with each other, and the environments they create🍃

A one-session class covering the primary computational methods of Code Societies Classes: Winter 2019. Together we will defamiliarize and refamiliarize ourselves with the Command Line Interface, Git/Github, running Python 3 in the terminal, & running Python 3 with Anaconda Jupyter Notebook. We will navigate folder structure narratives with the command line, time travel with Git, code socially with Github, and process language with Python.

🌿Before we begin…

You should have the following programs installed on your system:
- Atom
- Git
- Anaconda
- You should also have a GitHub account
Original syllabus lives here: https://docs.google.com/document/d/1nTAGOnsBCW5pTe0KfKtdEfqeSwC8YuFhBSad0Xu_Zdw/edit#heading=h.j1gmhmtgvufk
Download the folder at this link: https://drive.google.com/file/d/1DtBmjeguFjsyHmj8oqADk8NEv14g1bCh/view
Unzip the folder and move it into to your “home” or “root” folder (the one with the little house icon on a Mac).

Computational Methods of Code Societes: Melanie Hoff describing folder structures

🌿We can think of the “environment” as way that a programmer builds their personal workflow in the domain of their computer…

Coding isn’t something that just happens in your text editor or terminal. Coding can be a wholistic computer practice, a new relationship you have with your computer & your computer habits. from the way you name your files or organize your folders, to completely changing how you perform routine tasks on your computer such as moving a file.

To ensure that you can easily access Atom (the text editor we will be using throughout this guide) follow these steps:

Open Atom
Click the Atom menu in the top left corner and choose “install shell commands”. This will ensure that you can access Atom from the Terminal also known as the command line.

Computational Methods of Code Societes: Terminal example

🌿What is the command line?

Think about all of the applications you open on a day to day basis on your computer. One of the many mechanisms we use to do these things is dragging and clicking different icons and folders using a mouse or trackpad.

Let’s take a small tour of our computers by following these steps:

Open up a new Finder window.
Navigate to your home folder. It is helpful to use the “folder view”, you can do this by clicking the little icon with the three rectangles at the top of the Finder window.
Click on the code-societies folder
Notice that there are two folders inside of that folder
Now click on the computational-methods-code-societies folder
Notice that there is a folder called house
If you click on house you will notice a few more folders denoting the rooms in the house
Keep going!

This folder structure follows the structure of a house which is a spatial metaphor for how we navigate folders on our computer. For example, when you’re in a house and standing in the kitchen and you wanted to go to bed you would need to navigate from the kitchen into your bedroom before you actually tried to lay down.

Another way to do this kind of navigation is by using the command line, a text-based mechanism for doing the same kind of navigation between folders and files.

The command line can be seen a more intimate way to interact with your computer, it’s kind of like having a conversation, you can ask your computer to do something and it might respond to you with a confirmation of what you typed or some kind of prompt or a scrolling list of crazy words letting you know that it is in the process of installing some stuff or nothing at all!

sometimes you will ask your computer to install something and it will not give you any kind of response but the thing you wanted to install was actually successful. the reason the computer will not return any kind of response takes us way back into the history of computing when the computer would respond to a programmer by printing out its response on a piece of paper. In order to save paper computers were programmed to just do nothing if the command was successful.

Computational Methods of Code Societes: Terminal magic, photo of someone's Terminal garden

🌿Lets embark on a Folder Structure Narrative !

Moving forward you can think of the Terminal (command line) as the “secret trap door/master key/teleportation portal” to your computer.

The programming language of the terminal is called Bash. This is the language that allows us to write commands that the Terminal can understand so that we can do things like navigate the file system (as we did above) on our computers. Bash files, also known as scripts because they often execute pieces of code, look something like this name-of-bash-script.sh

Follow these steps to begin:

Press command and spacebar
Type in “Terminal”
Press Enter
When you open the Terminal you’ll see something called a bash prompt: You’ll see your user name and a ~ The ~ represents your home directory.
You can verify that you’re in the home directory by typing ls and pressing enter. You should see a list of all of the folders and files directly inside of your home directory.
You change directories from your home directory by typing cd and pressing enter.
If you type in cd code-societies your bash prompt will now look something like this your username:code-societies$
Remember you can verify that you’re in the a particular directory by looking at your bash prompt as well as by running the ls command. With the ls command you should see all of the folders and files inside the directory you are currently in.
From the code-socities folder you can cd into computational-methods-code-societies
Finally you can cd in the house folder.
Welcome to the house tour! Lets cd into the kitchen!
Run ls. Do you see the file pots-and-pans.txt ?
Try running this command cat pots-and-pans.txt
This cat command will display all of contents of that file right inside your terminal ! How beautiful !
Now you lets cd into the garden
Run ls again and notice a file called grow.sh. We know this is a bash script because of the .sh. This means that we can execute this script (or program) inside of terminal.
To see the bash script in action type bash grow.sh and press enter. A bunch of beautiful flowers should appear!
Notice if you run cat grow.sh you will see the contents of the script that produced the bunch of beautiful flowers!

The commands we’ve learned so far are: cd ls cat bash

Some more helpful commands: pwd open . opens the folder you are currently inside of cd .. changes directories in reverse tab key to autocomplete up and down arrow keys touch creates a new file atom . opens the folder you are currently inside of with Atom mkdir makes a new directory touch myfile.txt creates a new file called myfile.txt rm foldername removes a folder called foldername rm filename.txt removes a file called filename.txt say asks your terminal to say whatever you have types

If you try to run cat on a jpg file the terminal will print out all of the “text” for the file.

🌿Now you can create your own Folder Structure Narrative

Example of artist, Ryan Kuo who used navigating a generic looking Mac Application to talk about navigating family dynamics in his piece, Family Maker

Run cd .. as many times as you need until your bash prompt tells you that you are inside of the computational-methods-code-societies folder
We will use the mkdir command to create some new folders. mkdir stands for make directory. For example, you can run mkdir my-new-folder and that folder will be created inside of your computational-methods-code-societies directory.
Use the touch command to create new files within the folders. It is helpful to make sure that the names of your folders and files do not have spaces or capital letters
Use cd name-of-folder and cd .. to move in and out of folders
Use rm -rf name-of-folder-or-file (remove recursive force) to delete items but be careful you can’t undo this!
If you see a bash command and you want to know exactly what it does you can use the man command, for example man ls will show you what ls stands for. You can press q to exit the explanation.
If you want to see hidden files (files that start with a dot) within a directory you can run ls -AF
You can run the clear command to refresh your terminal window.

🌵Some more Folder Structure Narrative examples

🌿What is git??

A version control and time travel software! Suspend your belief for just a moment!

To begin cd .. and cd .. again until you are inside computational-methods-code-societies

✨Enter the command: git init Now follow these steps:

git add .
cd time-travel/
ls
You should now see a folder called sensations.txt
atom .
Edit the sensations.txt file in Atom

For the next 60s ⏲, inside the sensations.txt file write down the small sensations and sounds you’re experiencing right now in this moment. Volume of words > coherence
Save the file and go back to terminal.
git commit -am “my first sensations”

Repeat steps 6 - 7 two more times;

Make sure you git commit -m “my second sensations” + git commit -m “my third sensations”
git log
Copy one of the hashes from one of your commits. The hash looks something like this 6c750cb264c6d5ad0fac18863cafd0df35315fce
Press q to exit log
git show <place your hash here> this allows you to review the detailed history of a given change

Now we’re going to time travel!!

git checkout <place the hash of your first commit here>

This is like traveling through time to past versions of yourself and the record of the sensations you were feeling at multiple distinct moments in the past 🔮

Advanced, optional: rewriting history with git rebase

🌿What is GitHub?

Git is an open source software that GitHub capitalizes on. Git allows for collaboration. GitHub will allow you to save, and edit and update your code. For this guide we will be pushing our Folder Strucuture Narrative up to a new GitHub repository

Make sure to run git checkout master to go back to your latest code (all three sensations).

Login to GitHub or create account.
Go to repositories page and click new,
Name it computational-methods-code-societies
Click the Create Repository button
Type git remote rm origin (this ensures that you will be able to add your own github repository as the origin)
Follow the instructions at your GitHub repository for “push to an existing repository”
Copy each of the following commands one at a time, paste it into the terminal and press enter
git remote add origin
Before running the following command you should ensure that all of your files and folders are ready to be added to your repository. You can do this by running git add . Keep in mind that git only cares about files, so it will not upload folders if they don’t have files inside of them.
Now you can run git commit -am “name of message” (the message describes what you are adding)
Now type git push -u origin master (the name origin is just a naming convention and is referring to the url for your repository)
Prompt for username and password: Passwords are invisible in terminal
Optional: setting up ssh keys, if you don’t want to constantly enter your username and password

Common workflow: git pull make changes save file changes run git status to see a list of what files changes have been made git commit -am “my changes message” git push

Partner Activity

Fork the computational-methods-code-societies repo of your partner
Rename this forked repo on your github via the Settings button to include their name
Press the green Git Clone button and copy paste: git clone <the url of the forked repo> into your terminal (make sure that you are doing this inside your home directory)
Now you have a copy of your partner’s repo on your computer.
Take a look at your partner’s invented Folder Structure Narrative from earlier in class.
Using terminal, build on top of what your partner was going for with their narrative.
git add .
git commit -am “my addition to my partner’s narrative”
git push

Computational Methods of Code Societes: Code Societies students embark on folder structure narratives.

🌿Python

There are a lot of different ways to interact with Python. One way is using the interactive interpreter. Another way is using Jupyter Notebooks. In this guide we will mostly be working within a Jupyter Notebook.

Don’t forget to check out Nabil’s workshop Mathematics as Religious Experience on Dec 23

To ensure that Python is installed:

Type word python and press enter you should get back something like this Python 3.7.1 (default, Dec 14 2018, 13:28:58)[Clang 4.0.1 (tags/RELEASE_401/final)] ::

Computational Methods of Code Societes: Nabil leads us through Python code, terminology and conventions

Python terminology + conventions

In terminal you can write print(hello world) and the terminal will print out the line “hello world”. In Python you will usually write the name of the function, open parentheses, argument, closed parentheses

When learning to program make sure to give yourself time! Check out the book Teach yourself programming in 10 years

Now we will do some more things with Python:

Open atom
Create a new file
Paste in the following: sensations = open(“sensations.txt”)
Creating a variable that is going to store the information inside sensations.txt. Open is telling my computer to looks for a file called sensations.txt within the directory that you are currently in. Don’t forget to use quotations for your file name!
Now add print(sensations) This will print out whatever is inside of the variable sensations. Terminal will return: <_io.TextIOWrapper name='sensations.txt' mode='r' encoding='UTF-8'>

Loops

In the sensations.txt file add the following lines:

for line in sensations:
	print(line)

The sensations.txt file should now look like this:

sensations = open("sensations.txt")

for line in sensations:
	print(line)

Now you can save the file and go back to the Terminal.

In the terminal you can write jupyter notebook and press enter. This will automatically open up a new browser window.

Programming is like magic :)

Click on Introduction to Python file.

How can we work with these python notebooks?

Here is a list of Jupyter Notebook Keyboard Shortcuts:

shift + enter run cell, select below.
ctrl + enter run cell.
option + enter run cell, insert below.
A insert cell above.
B insert cell below.
C copy cell.
V paste cell.
D , D delete selected cell.
Use down arrow key to navigate to next section or block of code
When clock of code is highlighted in blue you can press command enter (or control enter) to run it (you can press the button also!)
Debugging

think like a scientist and come up with a hypothesis for what you think is going on then do a series of test to try and prove yourself wrong

Once we have gotten to the end of the file remember that we need to open the file again before we can successfully run it!
Make sure to read the error messages. Try your best to understand what the computer is saying.

For example: - Traceback (most recent call last) is referring to the most recent place in the code where an error was found - Io stands for input ouput

Perhaps the #1 programming skill is “googling the error message”

More resources:

https://drive.google.com/file/d/1gxjTV0SjIgedS7mGaLGwwf6_-7w380lL/view
https://devhints.io/

✿ this guide was compiled by emma @doodybrains rae norton

Code Societies Winter 2019