1. This lab bas 3 Tasks (3^rd task has several parts). You should try to do these parts at

Task 2 and 3 are in the interactive textbook. Watch the video I provided (follow the link at page 7) before doing these two tasks.

2. And 5 programming exercises (0 to 4)

The slides that are included here but do not explain either Tasks or Programming exercises are there as reminder of some relevant material that is needed for this lab.

Lab 3 overview

• Open a browser and log into Brightspace
• On the left hand side under Labs tab, find lab3 material contained in either lab3-students.zip or lab3-studnets.pdf file
• Download that file to the Desktop and open
• Read slides one by one and follow the instructions explaining what to When stuck ask for help from TA. Ideally you should try to complete some, or all of this, at home and then use the lab as a place where you can get help with things you may have had difficulties with.

Before starting, always make sure you are running Python 3

This slide is applicable to all labs, exercises, assignments etc

ALWAYS MAKE SURE FIRST that you are running Python 3.4 (3.5

and 3.6 are fine too). That is, when you click on IDLE (or start python any other way) look at the first line that the Python shell displays. It should say Python 3.4 or 3.5 or 3.6 (and then some extra digits)

If you do not know how to do this, read the material provided with Lab 1. It explains it step by step

div // and mod % operators in Python

If uncertain, here is how to compute a//b (i.e. integer division) and a%b (i.e remainder)

1. Compute x=a/b
2. a//b is then equal to the whole (i.e integer) part of More precisely a//b is equal the integer that is closest to a/b but not bigger than a/b
3. a%b is equal to a (a//b) * b

Task 1

What is the type and value of each of the following expressions in Python? Do this in you head (and/or paper) first. The check both columns in Python shell. eg. You can test what kind of value the first expression returns by typing type(13*0.1) in Python shell

Expression	Type	Value
13 * 0.1	float	1.3
int(13) * 0.1
13 * int(0.1)
int(13 * 0.1)
13 % 7
6%3
6//2.5
6%2.5
2<3== 4<5

6

Interactive textbook (Reminder)

Here is a link to the interactive textbook: https://runestone.academy/runestone/static/thinkcspy/index.html

Task 2: Debugging

Follow this link, and read, run and do the exercises there:

https://runestone.academy/runestone/static/thinkcspy/Debugging/HowtoAvoidDebugging.html

An example used in the above link refers to the following problem from Chapter: Simple Python Data, Section: Exercises, Question 3:

https://runestone.academy/runestone/static/thinkcspy/SimplePythonData/Exercises.html

Many people keep time using a 24 hour clock (11 is 11am and 23 is

11pm, 0 is midnight). If it is currently 13 and you set your alarm to go off in 50 hours, it will be 15 (3pm). Write a Python program to solve the general version of the above problem. Ask the user for the time now (in hours), and then ask for the number of hours to wait for the alarm. Your program should output what the time will be on the clock when the alarm goes off.

Programming exercise 0:

More debugging and coding

Open file q0.py and solve the 3 programming exercises as instructed.

Boolean Expressions

Boolean expressions evaluate to True or False

Logical/Boolean operators in Math and Python:

Math Python

AND and

OR or

NOT not

Here is how your compare two variables a and b in Math and Python

Math	Python
a = b	a == b
a b	a <= b
a b	a >= b
a b	a != b

Truth table

A TRUTH TABLE for a compound Boolean expression shows the results for all possible combinations of the simple expressions:

Testing if two strings are equal

For one of the programming exercise you will need to know that how to compare if two strings are equal. You can do that simply buy using == operator. Here are some examples

>>> A==A

True

>>> Anna==Anna

True

>>> Anna=anna

False

>>> a=June

>>> a==june

False

>>> a==June

True

>>> b=Ju + ne

>>> a==b True

1. Do not copy paste the above into python shell. It will likely give you syntax errors since quotes do not copy/paste correctly from Word.

Examples of compound boolean expressions:

• This is how you would test if age is at least 18 and at most 65:

age>=18 and age <= 65

• not is an operator to negate the value of a simple or compound Boolean Suppose age = 15. Then: age > 16 evaluates to False, and not(age > 16) evaluates to True
• Suppose day refers to a string which is a day of a Here is how you would test if day is a weekend:

day==Saturday or day==Sunday

• Here are two ways to test if age is less than 18 and greater than Think about the 2^nd one
  • 1^st way: age<18 and age > 65
  • 2^nd way: not(age>=18 and age <= 65)

Task 3: if statements

Follow all the links below. Read, run and do the exercises in each of them. No need to watch the videos.