Physics MSc & CDT Programming Induction: Collaborative Notes

http://tiny.cc/ucl_sc

Staff

DAY 1:

Instructors: Ben (Bash) & David Pérez-Suárez(Git)
Helpers: Tara, Nathan, David Wong, Elizabeth (AM), Marin (PM)

DAY 2:

Instructors:
Helpers: Tara, Nathan, Elizabeth (AM), Marin (PM)

Notes

Contribute to this document by adding notes about the class below.

Bash

• ls lists the files
  • ls -F shows the folders by adding a / at the end of the folders, those ending with * are executable files.
  • ls -a shows all files including those starting with a . (Hidden files).
• man ls or in Windows ls --help shows the help for the ls command.
  To get out of the help pages you need to press q.
• pwd prints the working directory
• tab key is very powerful, autocompletes between the command or the files available. E.g., ls D + tab will show that can be either “Documents”, “Downloads” and/or anything that starts with D.
• ⬆/⬇ browse through the previous commands (your shell history).
• clear cleans up the screen (but doesn’t clean the history).
• cd change directory.
  • cd .. changes the directory into the one above (also works with ls - it will show you the content of the directory above)
  • cd without any argument it will move you to your home directory (i.e., /home/username, /Users/username or something similar).
  • cd ~ also takes you to your home, but you can also use it to got to something relative to that: cd ~/Desktop will move you to the Desktop no matter where you are.
• mkdir make a new directory.
• nano is a text editor that work directly on the command line
  • nano filename.txt will open (or create if doesn’t exist) a file called filename.txt
  • to save, exit or any other action you need to use the commands seen on the bottom. ^ means the key ctrl, so ^X for exit means pressing ctrl+x.
• touch filename will create a file.
• rm filename is for removing files.
• mv <source 1> <source 2> ... <source n> <destination> moves files from one place to another, destination is expected to be a directory.
  • mv <Old_file_name> <new_file_name> can be used to change file names.
• wc <filename(s)> gives a word count inside the file with format:
  • <#.lines> <#.words> <#.characters> <filename>
• sort putting digits into numerical order (with -n option) or words into alphabetical order
• head display the first line of a file
  • One can also specify the number of lines they want to display by using head -n <number_of_lines>
• tail similar to head but displaying from the last line.
• cat <filename> prints file contents in the terminal.
• [some_command] > output.txt writes the output of some_command to a file called output.txt, doesn’t need to be in txt format.
  • > overwrites what’s inside the file if it already exists.
  • >> appends to existing file.
• [command_1]|[command_2] the output of command_1 will be fed into command_2.
  • One can use a sequence of commands using this pipe function [command_1]|[command_2]|...|[command_n], the commands will run from 1 to n in order.
• cut cut each line of a file.
• echo print string.

Git

Python

1. Create a plot showing the standard deviation (numpy.std) of the inflammation data for each day across all patients.

2. Add your new plot to your previous group of plots

3. Change the plot figure so the plots are vertical and not horizontal

4.  # slice only the last 4 characters of the string
   
   
    string_for_slicing = 'Observation date: 02-Feb-2013'
    # slice only the last 4 items in the list 
    list_for_slicing = [['fluorine', 'F'],
                    ['chlorine', 'Cl'],
                    ['bromine', 'Br'],
                    ['iodine', 'I'],
                    ['astatine', 'At']]
   

5. beatles = "In an octopus's garden in the shade"
   # use string slicing to print `I notpssgre ntesae` from the `beatles` variable
   

6. # write a loop that sums up every element in this list
   numbers = [124, 402, 36]
   # should be 562
   

x = 5
coefs = [2, 4, 3]

y = coefs[0] * x**0 + coefs[1] * x**1 + coefs[2] * x**2
print(y)
# write a loop using enumerate do calculate the polynomial

Wrap up

• Post workshop survey
• Post-it notes. One good thing, one bad thing