ISYS90088
Introduction to Application Development
School of Computing and Information Systems University of Melbourne Semester 2 , 2018
Dr Antonette Mendoza
* Some slides are adapted from Fundamentals of Python by Kenneth A. Lambert and dept. resources
Lecture Agenda
l Introduction
l Objectives
l Staff;Learning&Assessment
l What is a computer, and how do we talk to it?
l Python
l Grok
l Python Basics – print, input, strings
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1-2
About me (Antonette)
l PhD in Computer Science – UoM
l 17 years @ UoM teaching
l Three Dept. and MSE Teaching Awards
l UniversityofMelbourneEdwardBrownTeachingAward(2017)
l AustralianAwardforUniversityTeachingaward(2017)
l Computing Research and Education (CORE) teaching award (2018)
l Coordinator – Tutor development Program in the MSE; New academic teaching development program in MSE; Graduate research coordinator in CIS
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About me (Antonette)
l Research focus:
Ø Expertise lies in the area of process modelling, design and development of emerging
technologies that support positive computing, adoption and longer-term use.
Ø Interests extend to exploring the impact of wider range of technologies that include mobile applications and social media platforms on society including health care, e- learning and telework.
l Grants:
Ø Ø
Ø Ø
Australian Research Council grant 2016 – 2018 Ø “Catering for individuals’ emotions in technology development”
CRC Low Carbon Living grant 2014 – 2017
Ø Increasing knowledge and motivating collaborative action on low carbon living through team-based and game-based
mobile learning’.
Other grants include: Learning and teaching grant 2015-2016; predictive tool for depression care NHMRC grant 2014 – 2015; aged care touch frame project; VVP project for industry client;
iPad app for assessment and feedback “Rapid Feedback” on iTunes in 2016. ISYS90088 sem 2 2018 4
About me (Antonette)
Contact details:
l Office:Room6.03DougMcDonnellBuilding
l Email: mendozaa@unimelb.edu.au
l Consultation: By appointment ( email me and I will give you a time to meet)
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Setting Expectations
What is Programming?
What is a Software development life cycle?
Is it important?
What do you expect to learn from this subject?
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What we will be studying
l Fundamentalconceptsandmodelsofapplicationdevelopment
l Students who have no background in application development or
programming.
l Learnaboutthesoftwaredevelopmentlifecycle,programdesign, data structures, problem solving, programming logic, implementation considerations, testing and enterprise level applications.
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Objectives
l Learn to use primitive data types and data structures
l Understand basic programming concepts
l Writesimpleapplicationsthatrelatetoaspecificdomain
l Design,implement,test,anddebugaprogramthatuseseachofthe following fundamental programming constructs: basic computation, simple I/O, standard conditional and iterative structures, and the definition of functions.
l Test applications
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Learning and Assessment
l Lectures, Labs
l Assessment
l Textbook & references
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Learning and Assessment
Lectures: Tuesday 2.15pm – 4.15pm in Redmond Barry (Lyle Theatre) Labs: 8 scheduled labs across the week – attend any one!
Workshop 1 Workshop 2 Workshop 3 Workshop 4 Workshop 5 Workshop 6 Workshop 7 Workshop 8
Tuesday18:15 Wednesday Wednesday Wednesday Thursday
Thursday
Thursday
Friday 17:15
Alan Gilbert-111
20:15 17:15 19:15 16:15 19:15 17:15 16:15
19:15 21:15 18:15 21:15 19:15 18:15 19:15
Alan Gilbert-111
Alan Gilbert-111 Engineering B-102
Alan Gilbert-111
Elec. Engineering-121 PAR-Engineering B-102 PAR-Alan Gilbert-111
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Learning and Assessment
Tentative Schedule:
l Week 01: Introduction
l No workshops in week 01
l Week02: Software development, data types and expressions
l Worksheet 1 – simple print and input stmt + how to work with grok + idle download
l Week03: math function + Conditions – for /while/if statement
l Worksheet 2 – data types, expressions
l Week04: Strings/sequences + math functions + Release ass 1 (10%)
l Worksheet 3 – related to if/for/while statement
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Learning and Assessment
Tentative Schedule:
l Week05: complete sequences+ Functions
l Worksheet 4 – sequences and conditions + assignment 1
l Week06: Complete Functions – submit assignment 1
l Worksheet 5 – functions & ass 1
l Week07: Mid-semester test (10%)
l Worksheet 6 – Review so far!
l Week08: Iteration – for loops + while
l Worksheet 7 – iteration
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Learning and Assessment
Tentative Schedule:
l Week09: complete + lists _ release assignment 2 (20%)
l Worksheet 8 – feedback mid semester test + work on assignment 2
l Week10: lists/dictionary
l Worksheet 9 – list/dictionary + assignment 2
l Week11: advanced functions & File I/O – submit assignment 2
l Worksheet 10 – advanced functions
l Week12: Any outstanding + exam revision (60%)
l Worksheet 11 – practice questions and/or catch-up
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Learning and Assessment
Assessment:
l Individual Assignment 1 (10%) due in Week 6
l One mid-semester test (10%) in Week 7
l Individual Assignment 2 (20%) due in Week 11
• Exam (60%) – end of semester (3hr and will be a hurdle)
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Learning and Assessment
Text books/references:
l Youmayuseanytextbookandreferences. l Somebooks/references:
Ø FundamentalsofPython–KennethA.Lambert Ø Therearegoodonlineresources(free)
Ø Check out: www.python.org
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LMS
l University’s “Learning Management System” l http://www.lms.unimelb.edu.au/
l Use your university email id and password
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A word about the LMS & other environments
l We will post all code from lectures (other than snippets from the \console”) on the LMS after each lecture;
Ø Itisagoodideatolookbackoverthecodetoensureyoufully understand it and play around with it yourself
Ø Make sure to attend Tutorials and labs
l You will work on GROK environment for your labs and assignments
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Academic Honesty
Ø In accordance with the University’s Academic Honest and Plagiarism Policy (which you should familiarize yourself with!):
https://academichonesty.unimelb.edu.au/
Ø All examinable work (GROK worksheet answers and all project work) that you submit for this subject must be your own!!
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Academic Honesty
Ø Commoncausesofbreachesinthepasthavebeen:
ü friendsaskingtolookoveryourcodeto“gethints” fortheir
own project
ü flatmatesaccessingyourcodeviaashareddesktopcomputerwith saved login details
ü studygroupswherethefacilitatorhasoversteppedthelineand provided sample code to help people along
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Academic Honesty
Ø Common attempts to escape undetected are:
ü changing the comments but not the code
ü changing variable names
ü rearrangingblocksofcode(sometimesbreakingthelogicinthe process!)
Ø Itisalltooeasytoautomaticallypickuponallofthese,andmany, many more, approaches using software plagiarism detection software … and we do check
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So what is appropriate?
Ø Youareencouragedtoshare/collaboratedirectlyoncodeforany non-examinable items (notably the worksheets questions) … and you will learn a lot from reading the code of others (including the sample solutions in the worksheets)
Ø Youareverywelcometodiscusswithfellowclassmatesyourapproach to worksheet questions and the projects, in conceptual terms, or in
terms of key data types or programming constructs used (just not with the aid of raw code)
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Break!!!!
Lecture Objectives
After completing this lecture, you will be able to:
l Describethebasicfeaturesofanalgorithm
l Explainhowhardwareandsoftwarecollaborateinacomputer’s architecture
l Compose and run a simple Python program
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Algorithms & Information Processing
Ø Computer science focuses on l Algorithms
l Information processing
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Algorithm – what is it?
Ø Sequenceofstepsthatdescribeseachofthesecomputational processes is called an algorithm
Ø Featuresofanalgorithm:
l Consistsofafinitenumberofinstructions
l Eachindividualinstructioniswelldefined
l Describesaprocessthateventuallyhaltsafterarrivingatasolution to a problem
l Solvesageneralclassofproblems
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Algorithm – example!
l Stepsformakingacupofcoffee!!!
Ø Imaginethatyouwantarobot(orafriend)tomakeit.
Ø Howwillyouexplainthisproceduretotherobot(oryourfriend)so they can make it?
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Algorithm – another example!
Ø Stepsforsubtractingtwonumbers:
l Step 1: Write down the numbers, with larger number above smaller
one, digits column-aligned from right
l Step2:Startwithrightmostcolumnofdigitsandworkyourway left through the various columns
l Step3:Writedowndifferencebetweenthedigitsinthecurrent column of digits, borrowing a 1 from the top number’s next column to the left if necessary
l Step4:Ifthereisnonextcolumntotheleft,stop
l Otherwise, move to column to the left; go to Step 3
Ø The computing agent is a human being
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Information Processing
Ø Informationisalsocommonlyreferredtoasdata
Ø Dataneedstobeorganizedandstoredinsomeformtoberelevant
and easily accessed!
Ø In carrying out the instructions of an algorithm, computing agent manipulates information
l Start with inputàdo something/taskàproduce output
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Structure of a Modern Computer System
Ø Amoderncomputersystemconsistsofhardwareandsoftware
l Hardware: physical devices required to execute algorithms
l Software:setofthesealgorithms,representedasprogramsin particular programming languages
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Computer Hardware
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Computer Hardware (continued)
Ø Random access memory (RAM) is also called internal or primary
Ø Externalorsecondarymemoryexample:cd;floppies magnetic disks; optical disks!!!
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Computer Software
Ø A program stored in computer memory must be represented in binary digits, or machine code
Ø Aloadertakesasetofmachinelanguageinstructionsasinputandloads them into the appropriate memory location
Ø Themostimportantexampleofsystemsoftwareisacomputer’s operating system
o Some important parts: file system, user interfaces (terminal-based or GUIs)
Ø Applications include Web browsers, games, etc.
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Computer Software (continued)
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Getting Started with Python Programming
Ø Early 1990s: Guido van Rossum
l invented the Python programming language
Ø Pythonisahigh-level,general-purposeprogramminglanguagefor solving problems on modern computer systems
Ø Usefulresourcesatwww.python.org
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Running Code in the Interactive Shell
Ø Python is an interpreted language
Ø Simple Python expressions and statements can be run in the shell
l Easiest way to open a Python shell is to launch the IDLE (Integrated DeveLopment Environment)
l To quit, select the window’s close box l Shellorcommandlineisusefulfor:
l Experimenting with short expressions or statements l Consulting the documentation
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Running Code in the Interactive Shell (continued)
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Input, Print, String Processing & Output
Ø Programsusuallyacceptinputsfromasource,processthem,and output results to a destination
l In terminal-based interactive programs, these are the keyboard and terminal display
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The print statement
A print statement evaluates the expression and displays them, separated
by one space, in the console window
l Syntax:
print (
>>>print (3)
3
l Ifyouwanttodisplayatext(inpythoncalledastring),thenthe string must be enclosed within quotations – single or double
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Strings in python
l Thewordstringisusedtodescribeapieceoftextinsidequotes.
l You’ve seen how Python can be used to manipulate numbers, but it is also useful to be able to manipulate text.
l The things you type into a Python program are expected to be Python commands.
Example:
>>>print (“hi there”) >>>print (‘hi there’)
>>>print (“what’s she doing”)
Lets run this and see what happens!!!!!
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Strings in python
l Suppose you want to represent the words Hello There as text inside a Python program. If you type them as is into the program directly, Python will try to treat those words as names in the Python language:
>>> print (hello there)
What happens? Lets check it out! We get an error message!!!!!
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Errors and python translator
l Sometimes, you will write something which the Python interpreter does not understand. The most basic kind of mistake you can make is a syntax error.
l A syntax error occurs when you type something which is not properly formed, according to the rules of the programming language.
l It is the same as a grammatical error in English (or any natural language for that matter).
l So, in this example it did not know what hello there is (not an identifier) until you tell it to be a string within quotes.
>>> print (‘hello there’) hello there
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print – examples
• Youcantypeinexpressionsanditwillcalculatetheanswerfor you (noting that the asterisk, or *, signifies multiplication):
>>>print (3 * 2) 6
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The input statement
• Python has a built-in function called input that can be used to get
keyboard input from the user as a string.
• The input function can be given a message to display, usually promptingtheuserwithwhatkindof informationtheprogramwants.
• A variable is a name for a value. When a variable receives a value, that value can be accessed using the variable name when required.
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The input statement – example
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Variables and the Assignment Statement
l A variable associates a name with a value
Ø Makes it easy to remember and use later in program
l Variable naming rules:
Ø Reserved words cannot be used as variable names
l Examples:if,for,whileandimport
Ø Name must begin with a letter or underscore _
l The rest of the name can contain zero or more occurrences of the following things:
Ø Digits (0 to 9) .
Ø Alphabetic letters.
Ø Underscores.
§ Names are case sensitive
Ø Example:WEIGHTisdifferentfromweight
Tip: use “camel casing” (Example: interestRate) 45
Variables and the Assignment Statement (continued)
l Nothing else is allowed in a variable name. Here is (incomplete) list of the things you can’t use anywhere in a variable name:
Ø Whitespace characters (the space, tab, new line).
Ø Hyphens (-)
Ø Quotation marks (single or double)
Ø Symbol characters such as: the question mark, the exclamation mark, brackets, and so forth.
l The following words having special meaning in Python (reserve words), and so they cannot be used for variable
Examples:
def, if, for, while, else, except, return, True, range, list, continue
46
Variables and the Assignment Statement (continued)
l Programmers use all uppercase letters for symbolic constants Ø Examples: TAX_RATE and STANDARD_DEDUCTION
l Variables receive initial values and can be reset to new values with an assignment statement
Ø Subsequent uses of the variable name in expressions are known as variable references
47
Variables : Example 1
#Which of the following are valid variable names?
a. length
b. _width
c. firstWord
d. 2MoreToGo
e. halt!
Solution: ????
48
Editing, Saving, and Running a Script
Ø We can then run Python program files or scripts within IDLE or from the OS’s command prompt
Ø Python program files use .py extension
Ø Running a script from IDLE allows you to construct some complex programs, test them, and save them in program libraries to reuse or share with others
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Editing, Saving, and Running a Script
Ø SelectNewFilefromtheFilemenu
Ø enter the python code/statements
Ø File/Save as (give a sensible name to your file. The extension will be.py)
Ø Torunthefileorcodeasapythonscript,selectRunmodulefrom the Run Menu
Examples using IDLE – shown in lecture
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Editing, Saving, and Running a Script (continued)
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Editing, Saving, and Running a Script (continued)
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Behind the Scenes: How Python Works
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Detecting and Correcting Syntax Errors
Ø Programmers inevitably make typographical errors when editing programs, called syntax errors
l The Python interpreter will usually detect these
Ø Syntax: rules for forming sentences in a language
Ø When Python encounters a syntax error in a program, it halts execution with an error message
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Detecting and Correcting Syntax Errors (continued)
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Install Python
l We will use Python v3.4 via GROK (on my machine 3.5.1)
l You just write it like a text and the python interpreter turns it into
machine code for you
l Get a copy of python for your own machine at home – there are free versions for Windows, MacOS and Linux
http://www .python.org/download/
l Portable version (USB) http://portablepython.com/
l AdvancedPythonDistribution(forscientificexperimentation)
http://www .enthought.com/products/edudownload.php
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Grok Learning environment
l GROK Learning is the web-based programming environment we will be using for the duration of this subject in your labs: https://groklearning.com/course/unimelb-isys90088-2018-s2/
l All you need to access the system is a browser, an internet connection and your GROK account
l Different modes of working in GROK: code, run, mark, terminal
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Summary
Ø Fundamental ideas of computer science l The algorithm
l Information processing
Ø Real computing agents can be constructed out of hardware devices
l CPU, memory, and input and output devices
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Summary (continued)
Ø Software provides the means whereby different algorithms can be run on a general-purpose hardware device
l Written in programming languages
Ø Languages such as Python are high-level
Ø Interpreter translates a Python program to a lower-level form that can be executed on a real computer
Ø Python shell provides a command prompt for evaluating and viewing the results of Python expressions and statements
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Summary (continued)
Ø IDLE is an integrated development environment that allows the programmer to save programs in files and load them into a shell for testing
Ø Python scripts are programs that are saved in files and run from a terminal command prompt
Ø When a Python program is executed, it is translated into byte code
l Sent to PVM for further interpretation and execution
Ø Syntax: set of rules for forming correct expressions and
statements in a programming language
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