CS 4950 Spring 2016

Lab 4

Open Firefox and find the class web page.

Open TextWrangler - use the finder window and go to applications.
Open a new text file, called Lab3.txt, to record your work today - you will paste in some of your command lines. The header of the file should look like:
CS 4950
Lab 4
March 11, 2016

Find the Terminal - use the finder window and go to applications and then utilities.

We are going to start out using the Python interpreter
In the terminal type Python to open then interpreter, then at the prompt type the following and enter
>>> print "hello world"

For each command you run, copy the command line and the output into your Lab4.txt file.

Create a list and a sum variable
>>> L = [2,3,4,5,6]
>>> sum = 0

Now add all of the elements in the list (you will need to hit enter to get back to the prompt after sum = sum + i)
>>> for i in L:
...     sum = sum + i
...
>>> print sum

Use the built-in function len() to get the length - number of elements in the list L

>>> len(L)

Use a simple if statement to check for an element in L
>>> if 3 in L:
...     print 'found it'
...

Now try out the arithmetic operators to do some computations and make some notes about what you observe
>>> 16*2+5/4
>>> (16*2+5)/4
>>> (16*2+5)/4.0
>>> 3**2
>>> pow(3,2)
>>> 3%2
>>> 5%4
>>> 6%4
>>> sqrt(2)
>>> import math
>>> print "math.sqrt(100) : ", math.sqrt(100)
Now work through the examples starting on page 128 in the interpreter (not as a script yet).

You can exit the interpreter by typing ^d (control d).

If you get to the end, put it in a script and try to run it.
Even if it is not in your script directory you can always run it from the directory where it is saved by typing:
python myscript.py
where myscript.py is the name of your file.

Turn it in:
Go to the CS Homework Submission System: https://www.cs.csustan.edu/cshomework/
Choose: instructor Martin
Spring 2016
CS4950
Lab4