CSCICMPE 4341 Topic Programming in Python Review Final

CSCI/CMPE 4341 Topic: Programming in Python Review: Final Exam Xiang Lian The University of Texas – Pan American Edinburg, TX 78539 lianx@utpa. edu

Review • Textbook – Self-Review Exercises – Quick Quiz – Exercises • Time – 8 am - 9: 45 am, May 14 (Thursday) • Place – ENGR 1. 290 (classroom) 2

Review • Lecture slides – Basic concepts in Python – Control Structures – Functions – Lists, Tuples, and Dictionaries – Introduction to Object-Oriented Programming – Graphical User Interface Components – Python XML Processing – Database & SQL 3

Review • Multiple Choices • True/False Statements • Programming – Debugging – Write the code • Bonus Question 4

Chapter 1: Python • Python is a scripting language – It is not compiled as an executable file • Python – Structured programming • Divide and conquer – Object-oriented programming • Class and object – Data encapsulation – Inheritance – Polymorphism 5

Chapter 2: Basic Concepts in Python Programming • Arithmetic operators and their precedence • Commonly used Python rules/functions – print() 6

Arithmetic Operators • Symbols – – – * / % ** // # multiply # divide # modulus # exponential # floor division • Order – Operators are done in order of parenthesis, exponents, multiply and divide (left to right), and lastly add and subtract (left to right) 7

Chapters 3 & 4: Control Structures • The syntax of basic sequence, selection, and repetition structures in Python – Selection • if, if/else, if/else – Repetition • while, for 8

Syntax of Control Structure total = total + Grade counter = counter + 1 if Grade>=60: print ("Passed") else: print ("Failed") 9

for Repetition Structure 10 • The for loop – Function range is used to create a list of values [0, integer-1] – range ( integer ) » Values go from 0 to given integer [integer 1, integer 2 -1] – range ( integer 1, integer 2) » Values go from first up to second integer [integer 1, integer 2 -1] – range ( integer 1, integer 2, integer ) » Values go from first up to second integer, but increases in intervals of the third integer – The loop will execute as many times as the value passed – for counter in range ( value ): 10

Chapter 5: Functions • Modules and pre-defined functions – import module. Name – math • math. floor () • math. ceil () – random • random. randrange() • Syntax of user-defined functions 11

Module math Functions • Module – Contains function definitions and other elements • All of which are related in some way – Calling a function • function. Name ( argument 1, argument 2 ) – The import keyword is used to include a module – Invoking functions from a module • Use the module name followed by the dot operator (. ) • module. Name. function. Name( argument ) 12

Random-Number Generation • The random module – Used to generate a random number for the programmer – Function randrange • Generates a number from the first argument up to, but not including, the second argument • Each number in the range has the same likelihood of being selected by the function – random. randrange(a, b) 13

User-Defined Functions • Definitions – Functions must be defined before they are used – def function. Name ( param. List ): • function. Name is a valid identifier • param. List is a comma separated list of parameters received • The actions of the functions then follows – They should all be indented appropriately – The actions are also called the block or the function body 14

Chapter 6: Lists, Tuples, and Dictionaries • Creation and manipulation of sequences – String – List – Tuple 15

Example of Sequences Name sequence (C) C[0] -45 C[-12] C[1] 6 C[-11] C[2] 0 C[-10] C[3] 72 C[-9] C[4] 34 C[-8] C[5] 39 C[-7] C[6] 98 C[-6] C[7] -1345 C[-5] C[8] 939 C[-4] 10 C[-3] 40 C[-2] 33 C[-1] Position number of C[9] the element within C[10] sequence C C[11] 16

Creating Sequences – List • Lists – Use brackets – Separate multiple items with a comma • list 1 = [1, 2, 3, 4] – Empty list • list 2 = [] • Length of the list – len (list 1) • list 1[0]=0 # OK! 17

Creating Sequences – Tuple • Tuples – Use parenthesis – Separate multiple items with a comma • tuple 1 = (1, 2, 3, 4) • tuple 1 = 1, 2, 3, 4 – Empty tuple • tuple 2 = () – Singleton (or one-element tuple) • singleton 3 = 1, • Comma (, ) after 1 identify the variable signleton 3 as a tuple • Error! – tuple 1[0]=0 18

Chapter 7: Introduction to Object. Oriented Programming in Python • Classes – Attributes • Private attributes • Class attributes – Methods • Constructor: __init__ • Get and Set methods • Destructor: __del__ • Objects – Creation of objects • Inheritance 19

Class Declaration • Defining a Class – Class header • Keyword class begins definition – Followed by name of class and colon (: ) – Body of class • Indented block of code – Documentation string • Describes the class • Optional • Appears immediately after class header 20

Class Declaration (cont'd) • Defining a Class – Constructor method __init__ • Executes each time an object is created • Initialize attributes of class • Returns None – Object reference (self) • All methods must at least specify this one parameter • Represents object of class from which a method is called • Called self by convention 21

Get and Set Methods • Access methods – Allow data of class to be read and written in controlled manner – Get and Set methods • Allow clients to read and write the values of attributes respectively 22

Destructors • Destructors – Method is named __del__ – Executed when object is destroyed • No more references to object exist – Performs termination housekeeping before Python reclaims object memory • Typically used to close network or database connections 23

Chapter 8: Graphical User Interface Components • Components – Label – Entry – Button – Checkbutton & Radiobutton 24

Entry Component – Text. Box • Textbox – Areas in which users can enter text or programmers can display a line of text – Created by Entry class • <Return> event occurs when user presses Enter key inside Entry component 25

Checkbutton and Radiobutton Components • Checkbox – – – Small white square Either blank or contains a checkmark Descriptive text referred to as checkbox label Any number of boxes selected at a time Created by class Checkbutton • Radio button – Mutually excusive options – only one radio button selected at a time – Created by class Radiobutton • Both have on/off or True/False values and two states – selected and not selected (deselected) 26

Chapter 9: Python XML Processing • XML documents – Tree structure – Tags – Elements – Data 27

Chapter 10: Database & SQL • Relational database – Database schema – A set of relational tables • SQL (Structured Query Language) – A database language – Syntax of SQL • Use Python to submit SQL to databases 28

Example of Table: Employees 29

SQL • A program might select data from the table to create a query result – E. g. , to retrieve the location of each department, in increasing order by Department number – SQL: • SELECT DISTINCT Department, Location FROM Employees ORDER BY Department 30

SQL Results 31

SQL on Books Database • SELECT * FROM table. Name – SELECT * FROM Authors – SELECT Author. ID, Last. Name FROM Authors • SELECT column. Name 1, column. Name 2, … FROM table. Name WHERE criteria – SELECT Title, Edition. Number, Copyright FROM Titles WHERE Copyright > '2014' 32

Example of Using pyodbc Package http: //en. wikibooks. org/wiki/Python_Programming/Dat abase_Programming import pyodbc DBfile = '/data/MSAccess/Music_Library. mdb' conn = pyodbc. connect('DRIVER={Microsoft Access Driver (*. mdb)}; DBQ='+DBfile) #use below conn if using with Access 2007, 2010. accdb file #conn = pyodbc. connect(r'Driver={Microsoft Access Driver (*. mdb, *. accdb)}; DBQ='+DBfile) cursor = conn. cursor() SQL = 'SELECT Artist, Album. Name FROM Record. Collection ORDER BY Year; ' for row in cursor. execute(SQL): # cursors are iterable print (row. Artist, row. Album. Name) # print row # if print row it will return tuple of all fields cursor. close() conn. close() 33

Good Luck! Q/A