Variables and Strings

• Variables are symbols that you can use to store data in a program.
• Strings are arrays of bytes representing Unicode characters, or simply put, any characters stored between quotations.
• Examples

  • Print function with strings

    print("Hello World")
    

  • Print function with variables

    greeting = "Welcome!"
    print(greeting)
    

  • Asking user for input

    name = input("What is your name? ")
    

  • Joining strings together (Concatenation)

    print("Dear " + name + ", welcome!")
    

  • Rules for variable names

    • No symbols, except underscore (_)
    • Cannot start with a number
    • Cannot used reserved keywords

Data Types and Casting

• Basic Date Types

  • Integers
    • whole numbers
  • Floats
    • number with numeral points
  • Strings
    • characters stored in quotations
  • Booleans
    • stores True/False values

• Casting

  • Casting is to convert the data type of a value or string.
    • int() - convert to integers
    • float() - convert to float
    • str() - convert to string
    • bool() - convert to boolean

• Example

  year = int(input("What is your birth year?"))
  age = 2022 - year
  print("You are now " + str(age) " years old!")
  

Mathematics Operators

Comparators

If... elif... else...

• We use this to do checking of statements.
• The order of if... elif... else... is important.
• Only if and elif needs a condition.