Information and Data Management (IDM) Lecture Notes (Theory & Python) - GRADE 9,0

Information & Data Management
Lecture Notes




Week 1 2
Python Lecture Videos 2
Lecture 1a: Python Lecture 5
Lecture 1b: Information Systems Topics Lecture 9

Week 2 14
Python Lecture Videos 14
Lecture 2a: Python Lecture 20
Lecture 2b: Information Systems Topics Lecture 22

Week 3 27
Python Lecture Videos 27
Lecture 3a: Python Lecture 31
Lecture 3b: Information Systems Topics Lecture 33

Week 5 38
Python Lecture Videos 38
Lecture 5a: Python Lecture 42
Lecture 5b: Information Systems Topics Lecture 43

Week 6 48
Python Lecture Videos 48
Lecture 6a: Python Lecture 51
Lecture 6b: Information Systems Topics Lecture 51

Week 7 53
Python Lecture Videos 53
Lecture 7a: Python Lecture 55
Lecture 7b: Information Systems Topics Lecture 55

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Week 1
Python Lecture Videos
Google Colab
• https://colab.research.google.com/
• New notebook
• Open a notebook via a shared link copy to drive then you can make changes
• Tutorial explanation download file to laptop, then upload to Google Colab

Variables and Data Types
• Variable assignment: giving the variable a value
o Variable = value
o Print (Variable) value
o You can assign numbers and text
o This is when a variable gets a value.
o When it is the first time the variable name appears, the Python interpreter records the name
and the initial value.
• Modifying the value
o Give the variable a new value
revenue = 130000
print(revenue)
revenue = 12000
print(revenue)
130000
12000
o Use the variable itself
print(revenue)
revenue = revenue - 1000
print(revenue)
12000
11000
o Using multiple variables
number_sold_units = 145234
unit_price = 12.60
total_revenue = number_sold_units * unit_price
print(total_revenue)
1829948.4
o A variable has to be assigned BEFORE being used otherwise, NameError
• Type
o Every variable has a type.
o The type indicates what does the value look like.
o The type indicates what you can do with the object.
o print(type(variable)) <class 'int'> or <class 'float'> or <class 'str'>
o Integer: number
o Float: number with decimals
o String: text
o Text + text will print it side by side
o Number + number will add the numbers together
o Text + number TypeError
• Type conversion
o A string that looks like a number can be converted to a number.
o Convert text to number (integer or float)
print (int('1234'))
• print (int('1234.2')) won’t work, 1234.2 is not an integer
• print (int('Hello')) won’t work, Hello is not an integer
print (float('1234.2'))
o Convert number to text

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To display a space, add a space string!
print(message + ' ' + str(ratio))
• Hello world 0.1187076923076923

• Quiz:

Input Function
• An input is a data that is given to the program from
outside the program.
• Typical inputs includes:
o Asking the user to type a value
o Reading from a file
o Reading a network connection
o Accessing a database
• We will focus on the first type of input: asking the
human.
o Use input to ask the user something
o Store the result in a variable
o This variable is of type str, it is a string
• Example




o write text and press enter




• If the user has to type numbers, then we need to convert the text to numbers.

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• Quiz:

Operations
• The mathematical operators have a priority when computing a result.
• This is called Operators precedence.
• Standard operators in order of priority:
o ** power (as in 3 ** 4 = 3 * 3 * 3 * 3)
o * multiplication (as in 3 * 2)
o / division (as in )
o + addition (as in 3 + 2)
o - substraction (as in 3 - 2)
• You can use this with numbers or variables




• Quiz




Output
• "Output" is when a program presents something to the user.
• The first kind of output is displaying some text on screen. For this, we use print
• Note that we can use either ' or " to enclose text.
o Mixing both will result in error SyntaxError
o print("Hello World") Hello World
o print(‘Hello World’) Hello World
• You can also display numbers and results of operations
o print(4) 4
o print(4+2*34) 72
• Numbers and strings are different things
o print("2 * 1234") 2 * 1234
o print(2 * 1234) 2468
• We can chain together some text and numbers