Chapter 2- types, Variables, Memory, Simple Input and Output I. Basic Programming

Input Process Output

II. Strings

1. 
   Using String
   

"a bit",

print("it is...")

print(

"""

/ ___| / | / |/ | | ___|

| | / /| | / /| /| | | |__

| | _ / ___ | / / |__/ | | | __|

| |_| | / / | | / / | | | |___

\_____/ /_/ |_| /_/ |_| |_____|

_____ _ _ _____ _____

/ _ \ | | / / | ___| | _ \

| | | | | | / / | |__ | |_| |

| | | | | | / / | __| | _ /

| |_| | | |/ / | |___ | | \ \

\_____/ |___/ |_____| |_| \_\

)

1. 
   When you put quotes around something, Python takes it literally. It prints exactly what is in the quotes. You can use double quotes or single quotes for a string.
   
   1. 
      teacher = “Mrs. Heineman” or teacher = ‘Mrs. Heineman’
      

2. 
   You can print multiple values with a comma in-between strings for example:
   

3. 
   Concatenate- adding together strings
   

2. 
   open Silly string program
   

4. 
   Long Strings- triple quoted string
   
   1. 
      Use when you have several lines of text that you want displayed together
      
   2. 
      longString=””” Sing a song of sixpence, a pocket full of rye,
      

When the pie was open, the birds began to sing.

Wasn’t that a dainty dish to set before the king?””
B. Escape Sequences with Strings

a. allows you to put special characters into your strings.

b. made up of two characters: a backslash followed by another character.

# Fancy Credits

# Demonstrates escape sequences
print("\t\t\tFancy Credits")
print("\t\t\t \\ \\ \\ \\ \\ \\ \\")

print("\t\t\t\tby")

print("\t\t\tMichael Dawson")

print("\t\t\t \\ \\ \\ \\ \\ \\ \\")

print("My hair stylist, Henry \'The Great,\' who never says \"can\'t.\"")

print("\a")

III. Math in Python

Mathematical Operations in Python

Operator	Description	Example	Evaluates to
+	Addition	7+3	10
-	Subtraction	7-3	4
*	Multiplication	7*3	21
/	Division ( true)	7/3	2.33333…
//	Integer Division	7//3	2
%	Modulus	7%3	1
**	Exponentiation	2**3	8

Evaluate the expression.

1. 
   3 + 5 5. 10//3
   

2. 
   -2*8 6. 10 % 3
   

3. 
   3**2 7. 20/3
   

4. 
   10/3 8. 20.0/3.0
   

Evaluate using order of operations.

1. 
   8 + 3*(6 + 1)
   

2. 
   3**3 + 4 * -2 – 3
   

3. 
   5 + 8 /4 * 3
   

4. 
   (2 + 3) ** 2 -10%2
   

5. 
   100%34 + 30/5
   

6. 
   6 + 2 – 5 * 2 +20%6
   

1. Integers …-3, -2, -1, 0, 1, 2, 3, ….

2. Decimal- floating point numbers 1.24, -0.3789 etc

3. Strings- characters contained in “ ” or ‘ ’

If you wrote the coding

score= score + 1 This line would add one to the value of score
Python short cut score+=1 means the same thing as the line above.

score-=1 would subtract one from the value of score

• 
  See Word Problem Program
  

1. 
   Variable exists when you assign a name to a value. A variable is stored in memory.
   

The result would be Mrs. Heineman on the screen.

2. 
   The equal sign is used to give the variable a value.
   
3. 
   Variables can be created for characters as well as numbers.
   
4. 
   Rules for Variable Names
   
   1. 
      Can have letters, numbers and underscore
      
   2. 
      Python is case sensitive
      
   3. 
      Must start with letter or underscore
      
   4. 
      No spaces
      
   5. 
      Use descriptive names
      
   6. 
      Name convention - intercap method- start with lowercase
      
      1. 
         firstName
         
      2. 
         middleInitial
         
   7. 
      try to keep within 15 characters
      
5. 
   Assigning variables
   
   1. 
      The variable name goes on the left side of the equal sign.
      
   2. 
      firstName=”John”
      

Look at the coding below. Predict what will happen next to each line. Then type and run program

# quote from IBM Chairman, Thomas Watson, in 1943

quote = "I think there is a world market for maybe five computers."
print("Original quote:")

print(quote)

print(quote.upper())

print(quote.lower())

print(quote.title())

print(quote.replace("five", "millions of"))

print(quote)

Examples :

name.lower()- would return the name in lower case

name.upper()- would return the name in upper case.

• 
  Run Trust Fund Buddy Bad
  

Logical Errors- program produces unintended results but does not crash.

1. 
   Converting Values
   

• 
  Run Trust Fund Buddy Good program
  

1. 
   How do you tell Python that a variable is a string instead of a number?
   

2. 
   Once you have created a variable, can you change the value that is assigned to it?
   

3. 
   With the variables teacher and Teacher, are they the same?
   

4. 
   Is “Hello” the same as ‘Hello’ in Python?
   

5. 
   Which of the following is not a correct variable name? Why?
   

1. 
   Teacher2
   
2. 
   2Teacher
   
3. 
   teacher_25
   
4. 
   TeaCher
   
1. 
   Is “10” a number or a string?
   

7. 
   Is ‘4’ the same as 4 to Python?
   

8. 
   State the output.
   

print (name.lower())

9. 
   Fix the statement so it converts to stated data type.
   
   1. 
      age=input(“Enter age”) #convert age to an integer
      
   2. 
      hourlyWage=input(“Enter wage”)
      

10. 
    Write a valid variable name for the following – state its data type.
    
    1. 
       Your grade point average.
       
    2. 
       Book title
       
    3. 
       Number of students in school
       
    4. 
       Your phone number
       

• 
  For each program make comments at the top with your name and the program’s name.
  
• 
  Use proper variable names
  
• 
  Make output “look nice”. It should never be just a number. For example:
  

• 
  Save all programs with proper name in your folder.
  

1. 
   Make a program that assigns your first name to the variable firstName; last name assigned to variable lastName and then display your first and last name with a space inbetween.
   

2. 
   Tipper Program- Write a program where the user enters the total of the bill from a restaurant order. The program should then display two amounts; a 15% tip and a 20% tip.
   

3. 
   Write a car salesman program where the user enters the base price of a car. The program should add on extra fees such as tax, dealer prep and destination charge. Make the tax be 7% of the cost of the car, dealer prep is $250 and destination charge is $130.50. Display the actual price of the car once everything is added in.
   

4. 
   Write a program that has the user input an amount in change less than one dollar. The program should output the number of quarters, dimes, nickels and pennies used for that amount. Assume it will give the most possible of the largest coins. For example: 92 is the inputted value.
   

Output:

The number of dimes: 1