msc-computer-science-notes

MSC Software Engineering Lesson Notes

This module is for MSC Software Engineering lessons notes.

Overview

WEEK 1

Main Topics

Sub titles:

Variables

  In [5]: num1 = 6
  In [6]: num2 = 105
  In [7]: sum = num1 + num2
  In [8]: product = num1 * num2
  In [9]: quotient = num2 / num1
  In [10]: difference = num1 - num2
  In [11]: print(f"Sum: {sum}, product: {product}")
  Sum: 111, product: 630

  In [12]: print(f"Quotient: {quotient}, difference: {difference}")
  Quotient: 17.5, different: -99

In [13]: wholeNum = 105//6
In [14]: remainder = 105 % 6
In [15]: print(f"Whole number: {wholeNum}, Remainder: {remainder}")
Whole number: 17, Remainder: 3

</br>alt text

Decision / Conditions

In [1]: num1 = 56                                                     
In [2]: num2 = 37                                                     
In [3]: if num1 > num2:
     ...:     print(f"{num1} is larger than {num2}")
     ...: elif num1 < num2:
     ...:     print(f"{num1} is smaller than {num2}")
     ...: else:
     ...:     print("Both numbers are the same.")
56 is larger than 37

Single line conditions

Condition statements

</br>alt text

Loops

* for loop :

  In [1]: for i in range(3,6):                                           
    ...:     print(i)
    ...:     
    3
    4
    5

In [2]: count = 0
In [3]: while count <= 4:
   ...:     print(count)
   ...:     count += 1
   ...:     
0
1
2
3
4


 In [4]: while count < 6:
   ...:     print(count)
   ...:     count +=2
   ...: else:
   ...:     print("Finished!")
   ...:      
0
2
4
Finished!

Best Practice

i = x + 1             # clear
i=x+1                 # not so clear

# grouping to make related operators and operands clearer
a = (b+4) * (c-7)           # clear
a = ( b + 4 ) * ( c - 7 )   # not so clear 

# a single line comment or

# a block comment both use 
# the hash symbol

area = pi * radius**2  #comment after a line of code

Strings and I/O

In [1]: myString = "Blue Birds."
In [2]: myString[5]
Out[2]: 'B'

In [3]: endOfString = myString[3:]
In [4]: endOfString
Out[4]: 'e Bird.'
In [5]: middleOfString = myString[3:6]
In [6]: middleOfString
Out[6]: 'e B'

Formatting Strings

In [7]: firstName = "Frank"
In [8]: age = 34
In [9]: "My name is {} and I am {} years old.".format(firstName, age)
Out[9]: 'My name is Frank and I am 34 years old.' 

In [10]: f"My name is {firstName} and I am {age} years old."
Out[10]: 'My name is Frank and I am 34 years old.'

In [11]: pi = 3.14159
In [12]: rad = 6
In [13]: cir = 2 * pi * rad
In [14]: f"A radius of {rad:.2f}cm gives a circumference of {cir:.2f}cm"
Out[14]: 'A radius of 6.00cm gives a circumference of 37.70cm'

# 42. Formatting numbers, first a float to 2dp, second an integer to 4dp float
print(f"42. I am {myHeight:.2f}m tall and weigh {myWeight:.4f}kg")

Console Output

In [15]: print("A string:", myString, "A number:", 1567)
A string: Blue Birds. A number: 1567

In [16]: print(56,78,"pink", sep="*",end="!")
56*78*pink!

Console Input

In [17]: name = input("Name: ")
Name: Frank
In [18]: num1 = int(input(f"{name} please enter a number: "))
Frank please enter a number: 45
In [19]: num2 = int(input("and a second number: "))
and a second number: 67
In [20]: sum = num1 + num2
In [21]: f"{name} the sum of {num1} and {num2} is {sum}."
Out[21]:'Frank the sum of 45 and 67 is 112.'


    try:
        myAge = int(input("Enter your age: "))
    except:
        print("Something has gone wrong")

Lab

def lab1():
    try:
        inputNumber = int(input("Enter Number: "))
        for i in range(2, 21, 2):
            result = i * inputNumber;
            print(f'{i} times {inputNumber:.2f} is  {result:.2f} ')
    except:
        print("there is a problem")

Left-sided Right-sided Diamond


def lab2():
    try:
        selected = int(input("Pres number of types that you want to select :  "
                             "\n 1-Left-sided "
                             "\n 2-Right-sided "
                             "\n 3-Diamond "))
        size = int(input("size :  "))
        text = "\n"
        for x in range(1, size):
            if selected == 1:
                text += str("*" * x) + "\n"
            elif selected == 2:
                text += str(" " * (size - x)) + ("*" * x) + "\n"
            elif selected == 3:
                if x <= size / 2:
                    text += str(" " * (size - x)) + ("*" * x) + (" " * (size - x)) + "\n"
                else:
                    text += str(" " * x) + ("*" * (size - x)) + (" " * x) + "\n"
        print(text)
    except:
        print("there is a problem")


def lab3():
    try:
        days = int(input("Count of days in a month : "))
        startWeekDay = int(input("Start week day : "))
        print("Calender")
        calender = "M\tT\tW\tTh\tF\tS\tSu"
        print(calender)
        startWeekDay -=1
        text = "\t" * startWeekDay

        for day in range(1, days + 1):
            if startWeekDay % 7 == 0:
                text += "\n"
            text += (str(day) + "\t")
            startWeekDay += 1
        print(text)

    except:
        print("there is a problem")

Data Structure

List[]

In [1]: myNum = 98
In [2]: myList = [45, 6.78, "Frank", myNum]
In [3]: myList
Out[3]: [45, 6.78, 'Frank', 98]

In [4]: myList[1:3]
Out[4]: [6.78, 'Frank']

In [5]: myList[-2]
Out[5]: 'Frank' 

In [6]: for x in myList:
   ...:     print(x, end="*")
   ...:     
45*6.78*Frank*98*

In [7]: if 'Frank' in myList:   
   ...:     print("Frank, You are in position:", myList.index('Frank'))
   ...:
Frank, You are in position: 2

In [8]: matrix = []
In [9]: num = 1
In [10]: for x in range(1,4):
    ...:     temp = []
    ...:     for y in range(1,5):
    ...:         num *= 2
    ...:         temp.append(num)
    ...:     matrix.append(temp)
    ...:     
In [11]: matrix
Out[11]: [[2, 4, 8, 16], [32, 64, 128, 256], [512, 1024, 2048, 4096]]

Tuple()

In [12]: myTuple = ("Cat", "Mouse", 56, 78)
In [13]: mySequence = 78,45,56,20
In [14]: type(myTuple)
Out[14]: tuple

In [15]: type(mySequence)
Out[15]: tuple

In [16]: anotherTuple = myTuple[0:2]
In [17]: anotherTuple
Out[17]: ('Cat', 'Mouse')

In [18]: type(anotherTuple)
Out[18]: tuple

In [19]: singleton = (45678,)
In [20]: singleton
Out[20]: (45678,)

Set{}

In [21]: mySet = {'A', '5', 5, "Jam"}
In [22]: mySet
Out[22]: {'5', 5, 'A', 'Jam'}
In [23]: mySet.add(5.0)
In [24]: mySet
Out[24]: {'5', 5, 'A', 'Jam'}

Dictionary{K:V}

In [25]: weekdays = {1:"Mon", 2:"Tues", 3:"Wed", 4: "Thur", 5:"Fri"}
In [26]: weekdays
Out[26]: {1: 'Mon', 2: 'Tues', 3: 'Wed', 4: 'Thur', 5: 'Fri'}

</br>alt text

Conversions

In [27]: nums = list(range(1,9,2))
In [28]: nums
Out[28]: [1, 3, 5, 7]

In [29]: names = ["Jan", "Sam", "Pam", "Joe"]
In [30]: numNames = zip(nums,names)
In [31]: listTuples =list(numNames)
In [32]: listTuples
Out[32]: [(1, 'Jan'), (3, 'Sam'), (5, 'Pam'), (7, 'Joe')]
In [33]: dictNames = dict(listTuples)
In [34]: dictNames
Out[34]: {1: 'Jan', 3: 'Sam', 5: 'Pam', 7: 'Joe'}


In [35]: fruit = ["apple", "pear", "banana", "grapefruit"] #Packing
In [36]: a,*b,c = fruit #Unpacking
In [37]: print(a, b, c)
apple ['pear', 'banana'] grapefruit

Activity 4: Data structures

1. Push
2. Pop
3. View

Functions

# A function definition with no arguments
def functionName ():
  statement1
  statement2

Arguments

# A single required argument passed in
def functionName (argument1Label):  

# Two required arguments passed in
def functionName (argument1Label, argument2Label):

# A variable length argument, 0 to many can be passed in
def functionName (argument1Label, args*, **kwargs):

# calling the function
funtionName("Normal", arg1, arg2, arg3, keyword1="value", keyword2="value"


# An argument with a default value 
def functionName (argument1Label="Default Value"):

In [1]: myList = [3,4,5]
In [2]: myList
Out[2]: [3, 4, 5]
In [3]: id(myList)
Out[3]: 4597091080
In [4]: def extend(aList):
   ...:     print(id(aList)    # Prints out the reference in aList
   ...:     aList.append([9,8,7])
   ...: 
In [5]: extend(myList)         # Pass myList into the function
4597091080                     # Outputs the id of aList (same as myList)
In [6]: myList
Out[6]: [3, 4, 5, [9, 8, 7]]   # MyList has changed
In [7]: id(myList)
Out[7]: 4597091080             # MyList id has not changed


In [8]: myList
Out[8]: [1, 2, 3]
In [9]: id(myList)
Out[9]: 4597265480
In [10]: def extendAgain(myList):
    ...:     myList = ['a','b','c']        # Creates a new variable
    ...:     myList.append([9,8,7])
    ...:     print("Function:",myList)
    ...:     print("Function", id( myList))
In [11]: extendAgain(myList)
Function: ['a', 'b', 'c', [9, 8, 7]]
Function 4597284296                    # myList has a different id
In [12]: myList                        # inside the function
Out[12]: [1, 2, 3]
In [13]: id(myList)
Out[13]: 4597265480

Return

# A function with a return statement that returns the contents of X
def functionName ():
  # do some stuff
  return X

In [14]: myList = [1,2,3,4]
In [15]: def swap(aList):
    ...:     a,b,c,d = myList             # Unpack 
    ...:     return b,d,a,c               # Reorder and pack
In [16]: swapList = swap(myList)
In [17]: swapList
Out[17]: (2, 4, 1, 3)
In [18]: type(swapList)
Out[18]: tuple

In [19]: def combine(nums, names):
    ...:     a,b,c = nums
    ...:     d,e,f = names
    ...:     return { a:d, b:e, c:f }
In [20]: names = ["Tanveer", "Fleur", "Takeo"]
In [21]: numbers = [1,2,3]
In [22]: myMap = combine(numbers, names)
In [23]: myMap
Out[23]: {1: 'Tanveer', 2: 'Fleur', 3: 'Takeo'}

Variable Scope

In [24]: name = "Tanveer"                      # Global variable
In [25]: def printHeader():
    ...:     title = "Employee of the month"   # Local Variable
    ...:     # Accessing both local and global variables
    ...:     print(f"{title}: ** {name} **")   
    ...:                               
In [26]: printHeader()
Employee of the month: ** Tanveer **
In [27]: title   # Variable no longer exists generates an error
-------------------------------------------------------------------------
NameError

Modules and Classes

Modules

# for a function that simply does something
FileName.functionName()

# Parameters can be passed the same as in any other
FileName.functionName(parameter1, parameter2)

# Values can be returned form the function, the same as in any other
variable = FileName.functionName()

Classes

class NameOfClass (object):

def __init__(self):

  self.variableName = parameterName

def myMethod(self):

variableName = MyObject()    #creating object from the class

varaibleName.MyMethod()      #accessing a method defined 
                             #in the class for that object

In [1]: class Person(object):
   ...:     def __init__(self, name, address, age):
   ...:         self.name = name
   ...:         self.address = address
   ...:         self.age = age
   ...:     
   ...:     def personalDetails(self):
   ...:         return self.name, self.address, self.age

In [2]: fleur = Person("Fleur", "Paris", 32)
In [3]: tanveer = Person("Tanveer", "Mumbai", 19)
In [4]: fleur.personalDetails()    
Out[4]: ('Fleur', 'Paris', 32)
In [5]: tanveer.personalDetails()
Out[5]: ('Tanveer', 'Mumbai', 19)

Inheritance (is a relationship)

super(localClassName, self).__init__()    # call to parent class # constructor
super(localClassName, self).methodName()  # call to extend a method from # parent class

In [6]: class Tutor(Person):
   ...:         id = 0
   ...:         def __init__(self, name, address, age, salary, id):
   ...:             super(Tutor, self).__init__(name, address, age)
   ...:             self.salary = salary
   ...:             self.id = id
   ...:         def personalDetails(self):
   ...:             return super(Tutor, self).personalDetails(), 
   ...:             self.salary, self.id 
   ...:            

In [7]: class Student(Person):
   ...:         def __init__(self, name, address, age, id):
   ...:             super(Student, self).__init__(name, address, age)
   ...:             self.id = id
   ...:
   ...:         def personalDetails(self):
   ...:             return super(Student, self).personalDetails(),self.id
   ...:      
   
In [8]: jane = Tutor("Jane", "New York", 45, 34000, 67930)
In [9]: jane.personalDetails()
Out[9]: (('Jane', 'New York', 45), 34000)
In [10]: takeo = Student("Takeo", "Tokyo", 23, "CMOD00045678")
In [11]: takeo.personalDetails()
Out[11]: (('Takeo', 'Tokyo', 23), 'CMOD00045678')

Composition (has a relationship)

In [12]: class Person(object):
    ...:     name = None   # Place holder for an object 
    ...:                   # that needs to be created
    ...:     age = 0       # setting a default value for an Integer
    ...:     pastJobs = [] # creating an empty List
    ...:     # CONTAINS: DOB object - reminder to add 
    ...:     # this to the constructor
    ...:     
    ...:     # A sketch for a constructor
    ...:     def __init__(self, name, age, dob): 
    ...:         None # yet to be defined

TODO:

WEEK 2

Main Topics

Sub titles:

Data encoding

Binary

Encoding vs Format

ASCII

Unicode

Universal Coded Character Set (UCS)

UTF-8

UTF-16 and UTF-32

File formats

Structured vs unstructured data

MetaData

Plain txt

docX

Comma Separated Values .CSV

eXtensible Mark-up Language .XML

JavaScript Object Notation .JSON

.yaml

HDF5 format

File input and output

Relative and Absolute Paths

</br></br>alt text</br>

Hidden characters

Reading from a file

open(file, mode, buffering, encoding, errors, newline, closefd, opener) 

In [1]: file = open("Pop_Goes_The_Weasel.txt")
In [2]: file.readline()
Out[2]: 'Half a pound of tuppenny rice,\n'

In [3]: file.readline()
Out[3]: 'Half a pound of treacle.\n

In [4]: file = open("Pop_Goes_The_Weasel.txt")
In [5]: file.read()
Out[5]: 'Half a pound of tuppenny rice,\nHalf a pound of treacle.\nThat’s the way the money goes,\nPop! goes the weasel.\n'

In [8]: file = open("Pop_Goes_The_Weasel.txt")
In [9]: print(file.read(10))
Half a pou

In [10]: file = open("Pop_Goes_The_Weasel.txt")
In [11]: for line in file:
    ...:     temp = line.rstrip('\n')
    ...:     print(f"** {temp:32}  **")
    ...:
** Half a pound of tuppenny rice,    **
** Half a pound of treacle.          **
** That’s the way the money goes,    **
** Pop! goes the weasel.             **

Writing to a file

In [12]: file = open("Pop_Goes_The_Weasel.txt", 'w')
In [13]: file.write("Humpty Dumpty sat on a wall.")
Out[13]: 28


In [17]: file = open("Humpty_Dumpty.txt", 'w')
In [18]: file.write("Humpty Dumpty sat on a wall.")
Out[18]: 28

In [19]: file.write("Humpty Dumpty had a great fall.")
Out[19]: 31

In [20]: file.write("All the king's horses and all the king's men")
Out[20]: 44

In [21]: file.write("Couldn't put Humpty together again.")
Out[21]: 35

In [22]: file.close()


In [16]: file = open("Pop_Goes_The_Weasel.txt", 'x')
-------------------------------------------------------------------------

FileExistsError                           Traceback (most recent call last)
<ipython-input-45-f7523625772f> in <module>()
----> 1 file = open("Pop_Goes_The_Weasel.txt", 'x')

FileExistsError: [Errno 17] File exists: 'Pop_Goes_The_Weasel.txt

In [23]: file = open("Humpty_Dumpty.txt", 'a')
In [24]: file.write("Half a pound of tuppenny rice,\n")
Out[24]: 31

In [25]: file.write("Half a pound of treacle.\n")
Out[25]: 25

In [26]: file.close()
In [27]: file = open("Humpty_Dumpty.txt")
In [28]: for line in file:
    ...:     print(line)
    ...:     
Humpty Dumpty sat on a wall.
Humpty Dumpty had a great fall.
All the king's horses and all the king's men
Couldn't put Humpty together again.
Half a pound of tuppenny rice,
Half a pound of treacle.

In [29]: file = open("Pop_Goes_The_Weasel.txt", 'r+')
In [30]: print("File pointer: ", file.tell())
File pointer:  0

In [31]: for line in file:
   ...:     print(line)
   ...:     
Half a pound of tuppenny rice,
Half a pound of treacle.
That's the way the money goes,
Pop! goes the weasel.

In [32]: print("File pointer: ", file.tell())
File pointer:  109

In [33]: file.seek(56,0)
Out[33]: 56

In [34]: file.write("All the king's horses and all the king's men\n")
Out[34]: 45

In [35]: print("File pointer: ", file.tell())
File pointer:  101

In [36]: file.write("Couldn't put Humpty together again.\n") 
Out[36]: 36

In [37]: print("File pointer: ", file.tell())
File pointer:  137

In [38]: file.seek(0,0)
Out[38]: 0

In [39]: for line in file:
    ...:     print(line)
    ...:    
Half a pound of tuppenny rice,
Half a pound of treacle.
All the king's horses and all the king's men
Couldn't put Humpty together again.

Binary access

In [40]: file = open("Pop_Goes_The_Weasel.txt", 'br')
In [41]: for line in file:
   ...:     print(line)
   ...:    
In [42]: print(file.read(1))
b'H'

Closing a File

      In [44]:  with open("Pop_Goes_The_Weasel.txt") as file:
    ...:     for line in file:
    ...:        print(line, end="")
    ...:           
    Half a pound of tuppenny rice,
    Half a pound of treacle.
    That's the way the money goes,
    Pop! goes the weasel.

Exception handling

</br></br>alt text</br>

In [47]: fileName = "myFile.txt"
In [48]: try:
...:     file = open(fileName)
...: except:
...:     print("An I/O error has been generated.")
...:     
An I/O error has been generated.

In [49]: import sys
    ...: fileName = "Humpty_Dumpty.txt"
    ...: try:
    ...:     file = open(fileName)
    ...:     line = file.read()
    ...:     words = line.split()
    ...:     value = int(words[0])
    ...: except FileNotFoundError:
    ...:     print("The file does not exist")
    ...: except ValueError:
    ...:     print("That is not a number")
    ...: except OSError as err:
    ...:     print("OS error: {0}".format(err))
    ...: except:
    ...:     print("Unexpected Error", sys.exc_info()[0])
    ...:     
That is not a number

In [50]: fileName = "Humpty_Dumpty.txt"
    ...: try:
    ...:     file = open(fileName)
    ...: except FileNotFoundError:
    ...:     print("The file does not exist")
    ...: else:
    ...:     for line in file:
    ...:         print(line, end="")
    ...: finally:
    ...:     print("\nClosing file")
    ...:     file.close()
    ...:     
All Humpty Dumpty sat on a wall.
Humpty Dumpty had a great fall.
All the king's horses and all the king's men
Couldn't put Humpty together again.
Closing file


In [51]: fileName = "MissingFile.txt"
    ...: try:
    ...:     file = open(fileName)
    ...: except FileNotFoundError:
    ...:     print("The file does not exist")
    ...: else:
    ...:     for line in file:
    ...:         print(line, end="")
    ...: finally:
    ...:     print("\nClosing file")
    ...:     file.close()
    ...:     
The file does not exist
Closing file

Re-raising an exception

In [52]: import sys
    ...: fileName = "MissingFile.txt"
    ...: try:
    ...:     file = open(fileName)
    ...: except BaseException as err:
    ...:     print("Unexpected Error caught: ", err)
    ...:     print("then passed else where")
    ...:     raise err
Unexpected Error caught:  [Errno 2] No such file or directory: 'MissingFile.txt'
then passed else where
--------------------------------------------------------------------
FileNotFoundError                       Traceback (most recent call last)
<ipython-input-17-4eebae96f330> in <module>()
      6     print("Unexpected Error caught: ", err)
      7     print("then passed else where")
----> 8     raise err

User-defined exceptions

Assertions

In [53]: num = 9
In [54]: num2 =20
In [55]: assert (num > num2), "num is too small"
--------------------------------------------------------------------
AssertionError                          Traceback (most recent call last)
<ipython-input-8-d7d11f55a261> in <module>()
----> 1 assert (num > num2), "num is too small"
AssertionError: num is too small

Regular expressions

Revisiting Strings

Python re library

Constructing a regular expression

RAW STRING

Using compile

In [56]: import re
In [57]: pattern = re.compile('.*U|Y.*Y|U')
In [58]: result = pattern.match("Universiy of York")
In [59]: if result:
    ...:     print("match")
    ...: else:
    ...:     print("no match")
    ...: 
match
In [60]: result = pattern.match("York has a University")
In [61]: if result:
    ...:     print("match")
    ...: else:
    ...:     print("no match")
    ...:     
match

Match object

Python String functions or Regex?

Parsing

CSV

XML

JSON

Databases

Relational

Structured Query Language (SQL)

Document Database

</br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br> </br></br>alt text</br>

Object orientated database

Production

Production 1: Data translation for storage

To enable a program to function each time it runs there needs to be an external and persistent data storage system that retains the state of the data. There are two considerations here. The physical storage medium for the data, such as a file or database and the format/structure of the data such as CSV or XML. This week you have explored a number of different formats in both regards as follows:

CSV XML JSON MongoDB SQL Database Other file formats? Select ONE format that you consider as most suited to the data in the scenario and the aims of the program. The format selected should support both the nature of the data and the aims of the application being designed. It should provide distinct advantages and minimal limitations over other data formats. It should not be selected solely because it is the easiest to program, although this can be included as an advantage if applicable.

Design:

Produce a model that shows how the data needs to be restructured to take best advantage of the selected format and work more effectively within the program. Where you have created groups or objects from the data show how they relate to each other.

Implementation:

Implement a parser that reads in the original data file. You may want to create a subset of the data file for testing and speed. Your program should then perform the translation from the original format/structure into your selected format. The result of this process should then be outputted to its relevant physical medium (files/database).

At this stage there is no requirement to handle data types (other than those inherent in the data format, i.e. numbers and “Strings”), conversions or missing data. The program can be demonstrated as a simple console based application, requiring the input of the file name by the user and sufficient output to demonstrate the correctness of the translation process.

Your program should produce regular output statements to the console so that it is easy to follow what the program is doing and provides a visual demonstration of the translation process. This will also be handy for any debugging required.

Reflection on design decisions:

Write a 200-word reflection that states the reason for your format selection and the advantages the format leads to the data and application and any limitations on the future use of this data within the selected format. You should consider what literature supports your reasoning/decisions.

TODO

WEEK 3

Main Topics

Sub titles:

Event driven programming

Designing with events

Formal tools

UML

State diagram notation

Closures and Lambda expressions

Closures

first-class entities

In [1]: def addValues(num1, num2):
   ...:     sum = num1 + num2
   ...:     return sum

In [2]: addValues(6,9)
Out[2]: 15

In [3]: myFunction = addValues
In [4]: myFunction(11,4)
Out[4]: 15

Nested functions and scope

In [11]: myNumber = 10
In [12]: def outerFun(val1, val2):
    ...:    global myNumber
    ...:    myNumber += val1
    ...:    print("Outer function:", myNumber, val1, val2)
    ...:    def innerFun(myNumber):
    ...:        myNumber -= val2
    ...:        print("Inner Funtion", myNumber, val1, val2)
    ...:        def ininnerFun():
    ...:            nonlocal myNumber
    ...:            myNumber += val1
    ...:            print("InInner Funtion", myNumber, val1, val2)
    ...:        ininnerFun()
    ...:    innerFun(myNumber)
    ...:    
In [13]: outerFun(5,2)
Outer function: 15 5 2
Inner Funtion 13 5 2
InInner Funtion 18 5 2
In [14]: outerFun(5,2)
Outer function: 20 5 2
Inner Funtion 18 5 2
InInner Funtion 23 5 2

Defining a closure

In [18]: def addValues(num1, num2):
    ...:   sum = num1 + num2
    ...:   def printSum():
    ...:     # uses enclosing scope
    ...:     print("The sum is: ", sum)
    ...:   # call to the nested sum
    ...:   return printSum
    ...: 
In [19]: result = addValues(13,17)
In [20]: del addValues
In [21]: result()
The sum is:  30

Lambda function

In [22]: x = lambda y : y * 2
In [23]: print(x(5))
10

In [24]: def includeVAT(price):
    ...:     return lambda x : (price * 1.2) * x
    ...: 
In [25]: itemCost = includeVAT(0.57)
In [26]: itemCost(10)
Out[26]: 6.84

In [27]: itemCosts = []
In [28]: for i in range(1,9):
    ...:     itemCosts.append(includeVAT(i))
In [29]: print("5 items at £7: £", itemCosts[6](5), "including VAT")
5 items at £7: £ 42.0 including VAT

Graphical user interface design

Interface components

Basic Design Principles and User Testing

Colors:

Further Reading:

User testing and evaluation

Introducing Tkinter for GUIs in Python

Thinker Packages

Main window

In [30]: from tkinter import *
In [31]: window = Tk()
In [32]: window.title("Main Frame")
In [33]: window.mainloop()

Adding Components

In [34]: from tkinter import *
In [35]: window = Tk()
In [36]: window.title("Main Frame")
Out[36]: ''
In [37]: window.geometry("200x50")
Out[37]: ''
In [38]: text = Label(window, text="Hello World")
In [39]: button1 = Button(window, text='Press Me!')
In [40]: button1.pack()
In [41]: text.pack()
In [42]: window.mainloop()

</br> </br>alt text</br>

Container Widgets

In [43]: from tkinter import *
In [44]: window = Tk()
In [45]: window.title("Main Frame")
Out[45]: ''
In [46]: window.geometry("300x100")
Out[46]: ''
In [47]: left = Frame(borderwidth=5)
In [48]: text = Label(left, text="Hello World")
In [49]: button1 = Button(left, text='Press Me!')
In [50]: left.pack(side='left')
In [50]: button1.pack()
In [51]: text.pack()
In [52]: window.mainloop()

Layout managers

import tkinter as tk 
from tkinter import ttk
window = tk.Tk()
window.title("Grid Layout")
window.geometry("400x200")

for i in range(0,12):
    ttk.Label(window, text='A'+str(i), anchor="center").grid (row=0, column=i, sticky='NSEW')
    window.grid_columnconfigure(i,weight=1)
for i in range(0,6):
    ttk.Label(window, text='B'+str(i), anchor="center").grid(row=1, column=i+(1*i), columnspan=2, sticky='NSEW')    
    
ttk.Label(window, text='C'+str(i), anchor="center").grid( row=2, column=0, columnspan=12, sticky='NSEW')    
window.grid_rowconfigure(0, weight=1)
window.grid_rowconfigure(1, weight=1)
window.grid_rowconfigure(2, weight=1)
window.mainloop()
    

In [64]:import tkinter as tk
    ...: from tkinter import ttk
In [65]: window = tk.Tk()
    ...: window.title("Place Layout")
    ...: window.geometry("400x200")
    ...: 
Out[65]: ''
In [66]: label1 = ttk.Label(window, text='A1')
    ...: label2 = ttk.Label(window, text='A2')
    ...: label3 = ttk.Label(window, text='A3')
    ...: label4 = ttk.Label(window, text='A4')
In [67]: label1.place(height=150, width=100, x=0, y=0)
    ...: label2.place(height=100, width=50, x=150, y=100)
    ...: label3.place(height=50, width=50, x=175, y=125)
    ...: label4.place(x=300, y=150)
    ...: window.mainloop()

Adding style

In [64]: lab1 = tk.Label(window, text='York', fg='SteelBlue', bg='LightGray')

In [65]: ttk.Style().configure("TButton", foreground='SteelBlue', background='LightGray')

In [66]: style1 = ttk.Style()
In [67]: style1.configure("Yell.TLabel", foreground="blue", background="yellow", padding=3)
...
In [68]: ttk.Label(window, text='A', anchor="center", style='Yell.TLabel')

Color

Sizing

Canvas component

In [69]: from tkinter import *
In [70]: window = Tk()
    ...: window.title("Canvas Example")
    ...: 
Out[70]: ''
In [71]: c = Canvas(window, width=350,height=400)
    ...: c.pack()
    ...: 
In [72]: # coordinates: x-y top-left, followed by x-y bottom right
   ...: c.create_rectangle(40, 40, 110, 110, fill="#FD6707", outline='#C5D906',)
Out[72]: 1
In [73]: # coordinates are: x-y top-left, followed by x-y bottom right (as a rectangle)
    ...: c.create_oval(90,120,190,170, width=10, outline='#FD6707')
Out[73]: 2
In [74]: # each pair of values is x-y for a specified point within the canvas space
    ...: star = [100, 140, 110, 110, 140, 100, 110, 90, 100, 60, 90, 90, 60, 100, 90, 110]
    ...: c.create_polygon(star, outline='#925BCC', fill='#C5D906', width=3)
    ...: 
Out[74]: 3
In [75]: img = PhotoImage(file="Sunrise.png")
    ...: c.create_image(20,180, anchor=NW, image=img)
    ...: 
Out[75]: 4
In [76]: window.mainloop()

</br> </br>alt text</br>

Implementing interaction

Binding event handlers

ttk.Button(window, text='GET', width=6, command=get_def)

In [77]: import tkinter as tk
    ...: from tkinter import ttk
    ...: 
In [78]: def get_def():
    ...:   term = term_entry.get()
    ...:   # clears the text box from previous entries
    ...:   output.delete(0.0, tk.END)
    ...:   if term in computer_defs:
    ...:     definition = computer_defs[term]
    ...:   else:
    ...:     definition = "sorry that term is not in the dictionary"
    ...:   output.insert(tk.END, definition)
    ...:   
In [79]: window = tk.Tk()
    ...: window.title("Computer Science Definitions")
    ...: window.configure(background='black')
    ...: 
In [80]: # text to output to the user
    ...: instruction='Enter a term you would like to know the definition of:'
In [81]: # adding a logo
    ...: logo = tk.PhotoImage(file="Logo.png")
    ...: tk.Label(window, image=logo, bg='black').grid(row=0,column=0, sticky='EW')
    ...: 
In [82]: # adding instruction for user
    ...: tk.Label(window, text=instruction, bg='black', fg='white', font='none 12 bold').
    ...: grid(row=1,column=0, sticky='EW')
In [83]: # create a text entry box
    ...: term_entry = tk.Entry(window, width=20, bg='white')
    ...: term_entry.grid(row=2, column=0)
    ...:
In [84]: # add a button
   ...: ttk.Button(window, text='GET', width=6, command=get_def).grid(row=3, column=0)
In [85]: # lable for output
   ...: tk.Label(window, text='\nDefinition:', bg='black', fg='white', font='none 12 bold').grid(row=4,column=0, sticky='EW')
   ...:   
In [86]: # output for the definiton (large text box)
    ...: output = tk.Text(window, width=75, height=6, wrap='word', background='white')
    ...: output.grid(row=5, column=0, columnspan=2)
    ...: 
In [87]: # create the dictionary to extract terms
    ...: computer_defs = {'term':'Def', 'term2':'Def2'}
   ...:   
In [88]: window.mainloop()

Special variables

import tkinter as tk
from tkinter import ttk

def change(event):
    userOutput['text']=entryValue.get()
window = tk.Tk()
window.title("Special Variables")

userInput = tk.Entry(window)
userInput.pack()
userOutput = tk.Label(window)
userOutput.pack()

entryValue = tk.StringVar()
entryValue.set("A  string")
userInput["textvariable"] = entryValue
userInput.bind('<Key-Return>', change)

window.mainloop()

import tkinter as tk
from tkinter import ttk
window = tk.Tk()
window.title("Favourite Programming Language")
window.geometry("400x200")

def show_best():
    user_selection.configure(text=languages.get(best.get()))
languages = {1:"Python", 2:"Perl", 3:"Java", 4:"C++", 5:"Ruby"}
best = tk.IntVar()
best.set(1)

tk.Label(window, text='Choose a language:').pack()

for val, language in languages.items():
    tk.Radiobutton(window, text=language, variable=best, value=val, command=show_best).pack()

tk.Label(window, text='You selected:').pack()
user_selection = tk.Label(window, text='none')
user_selection.pack()
window.mainloop()

</br> </br>alt text</br>

Other methods and constants

Further Reading:

Other event-driven contexts

Client-Server Architecture

Internet of Things (IoT)

Production

Design:

Produce a set of wireframe designs for the application. These do not need to be final, changes can be made after the formative submissions, however they should focus on giving a complete view of the applications interface (not a collection of different ideas for one part of the interface). It should be clear how one part of the interface leads to another, and where any additional windows are opened.

Alongside this produce a set of integration diagrams (state-machines are a possible option here) to demonstrate 2 or 3 key areas of interaction. It should be clear which aspects of the interface these interactions relate too.

Implementation:

Create a first iteration implementation of the interface design. This may include small adaptations that are different from the design but you should aim for at least 90% of the design being similar. That is to say it should be very clear that one (design) is a model of the other (implementation). Avoid designing via coding, you will find the result disjointed. The key to GUI is design on paper first build second.

Reflection on design decisions:

Write a 200-word reflection that states the reason for the selection of the layout and components for the interfaces design. Clearly identify which specific aspects of the requirements or data’s structure informed the decisions. You should consider what literature supports your reasoning/decisions

WEEK 4

Main Topics

Sub titles:

Mathematics refresher

Descriptive statistics

Set Theory

Matrix mathematics

Regression and correlation

Probability

Further reading

NumPy

Pandas

Preparing for data analysis

Data reading and writing

Serialization

Cleaning data

Note:

Production

Design:

Implementation:

Reflection on design decisions: