Linguistic Gaming with Python

Python Practice 1

As with all programming languages (and languages in general), practice makes perfect. These exercises are meant for you to practice your programming skills.

This first exercise is just meant to get you a little bit familiar with Python and with programming in general.

Note: all Python programs should be saved with the Suffix .py. This lets the computer and the Python interpreter know that the lines of code you have written are meant to be in Python.

Python Installation and First Steps

• Read Dawson's Chapter 1.
• If you want to use Python on your own computer, then follow his instructions for downloading Python.
• If Python works on your computer, then do the practical exercises in the chapter (follow along with the chapter).

IDLE vs. editors

Dawson works with an IDLE (Integrated Development Environment). This is not quite what we did in class. You can either work with IDLE as Dawson describes, or work with an editor and call up Python from the shell/terminal. The following exercises assume you are working with an editor and call Python up from the shell/terminal while working with MacOSX.

Calling up Python in the Shell

• Open a Unix window via XQuartz or the Terminal application.
• At the command line, type: python
• Python should now be ready and your screen should have something like the following information on it:

  Python 3.4.3 (default, Jul  1 2015, 14:12:32) 
  [GCC 4.2.1 Compatible Apple LLVM 6.1.0 (clang-602.0.53)] on darwin
  Type "help", "copyright", "credits" or "license" for more information.
  >>>
  

• Now type

  print("Hello World!")

• To exit the Python interpreter, type

  exit()

  quit()

  or CTRL-d (Control button together with "d"). This is in fact a general strategy for exiting Unix programs. If you are ever stuck in a Unix shell, try CTRL-c or CTRL-d.

Python 2 vs. Python 3

There has been a period of change-over between Python Versions. Most of the material found on-line (and the new books) assume Python 3. In this course, we will use Python 3, but we will be confronted by Python 2 every now and then. In fact, there are only a few major differences between the two and they are not hard to remember.
 

Differences between Python 2 and Python 3
Python 2	Python 3
print "Hello World"	print ("Hello World")
raw_input("\nPlease enter something:\n")	input("\nPlease enter something:\n")

Creating and Saving a Python Program: this is best done by using editors that work well for text/utf-8. Examples are emacs, Aquaemacs, vi, TextEdit, Notepad, Kommodo, Textwrangler). Another option are so-called IDE (integrated development environment). Students in the past have found that they prefer Kommodo.

Now write the following lines of code into an editor of your choice and save the program in a file called world.py.

A First Program

#world.py #simple first program for Python 3 print("Hello World!") #Output

The Program

• The first line is a comment (comments begin with a #). It states what this program is called (this is good programming practice).
• The second line provides a bit more information about the program. In general, it is to be recommended to comment as much as possible. One forgets very quickly why one has written what code. Comments also make programs a lot easier for other people to read.
• The third line is an instruction to produce output.

Exercise 1.1. Copy or type the program into an editor, save it and try it out.

Exercise 1.2. Add more print commands and try out the new version of the program.

You can run programs you have written and saved in a number of ways.

• You invoke a "run" command while working within an IDE/IDLE.
• You move to the directory where your program is stored.
  • In Unix, you move via the cd (change directory) command. For example:

    cd my-programs

  • Note: try to avoid using empty spaces in your file or your directory names. Unix can deal with it, but it is messier.
  • When you are in the right directory, call up Python and give it the file name as an argument. For example:

    python printing.py

  • Output should now appear on your screen.

Dawson Exercises
 
Do the "Challenges" at the end of Dawson's Chapter 1.

Pretty Printing
 
Now let's move on to some pretty printing. The aim is to get a nicely formatted list with names and office information. Like this:

Name                 Place
-----------          -------
Miriam Butt	     G220
MacRoom              G209
Common Room          G119

Exercise 1.3. Type in or copy the program below into an editor, save it and try it out.

Exercise 1.4. What do the comma, the "\n" and the "\t" do? (\n generally stands for "newline")

Exercise 1.5. Now write a program that produces the above list of names with places, all nicely formatted.

Printing

#printing.py print("Miriam") print("Yassin") print("Miriam"), print("Yassin") print("Miriam "), print("Yassin") print("Lexi\t"), print("Levi") print("Lexi\tLevi") print("Miriam\nYassin")

End