Day 1 Solutions

Day 1 materials can be found here

Part II: If statements

1. Define a numeric variable, and use an if/else statement to determine if the number is greater than zero. Your code should print a sentence indicating if the number is greater than zero or not.

        x = 72
        compare_to = 0
        if x > compare_to:
            print(x, "is greater than", compare_to)
        else:
            print(x, "is not greater than", compare_to)
   

2. Modify the above if/else statement to write an if/elif/else statement to determine if the variable is greater than, less than, or equal to zero. Again, print a sentence indicating the number’s value relative to zero.

        x = 72
        compare_to = 0
        if x > compare_to:
            print(x, "is greater than", compare_to)
        elif x < compare_to:
            print(x, "is less than", compare_to)
        else:
            print(x, "is equal to", compare_to)
   	
   

3. Define two numeric variables, and use if/elif/else statement to determine which variable is larger (hint: they might be equal!). Again, print a sentence indicating which value is larger. This sentence should include both variable values.

   • The solution to this question is contained within #2 above.

4. Define a variable animal = "python". This type of variable is a string, meaning it is made of characters and defined with quotation marks. Write an if/elif/else statement to determine if the there are more than 10 letters in the variable animal (Hint: use the len() function!). Have your code print an informative message.

        animal = "python"
        compare_to = 10
        if len(animal) > compare_to:
            print("length is greater than", compare_to)
        elif len(animal) < compare_to:
            print("length is less than", compare_to)
        else:
            print("length is equal to", compare_to)
   

5. In Texas, you can be a member of the elite “top 1%” if you make at least $423,000 per year. Alternatively, in Hawaii, you can be a member once you start making at least $279,000 per year! Finally, if you live in New York, you need to earn at least $506,000 a year to make the cut. Andrew is CEO of Big Money Company, and he earns $425,000 per year, and Stacey is CEO of Gigantic Money Company with an annual salary of $700,000. Use a series of if statements to determine, and print, whether Andrew and Stacey would be considered top 1%-ers in Texas, Hawaii, and New York each. For this task, you should:

   • Define specific variables for the elite thresholds
   • Define specific variables for each person
   • Compare the variables to one another (as opposed to directly comparing numbers)

       ### Define 1% limits
       texas = 423000
       hawaii = 279000
       newyork = 506000
   		
       ### Define salaries
       andrew = 425000
       stacey = 700000
   	
       ### Compare Andrew
       if andrew >= texas:
           print("Andrew is elite in Texas")
       if andrew >= hawaii:
           print("Andrew is elite in Hawaii")
       if andrew >= newyork:
           print("Andrew is elite in New York")
   			
       ### Compare Stacey
       if stacey >= texas:
           print("Stacey is elite in Texas")
       if stacey >= hawaii:
           print("Stacey is elite in Hawaii")
       if stacey >= newyork:
           print("Stacey is elite in New York")
   			
   

Part III: Working with strings

First, define the following variables:

	mammal  = "orangutan"
	bird    = "sparrow"

1. Print a statement that reads “My two variables have values orangutan and sparrow.” Make sure to use your variables when printing (do not simply copy/paste this sentence).

        print("My two variables have values", mammal, "and", bird)
   

2. Use indexing to print the third character in each of the two variables (hint: it’s “a” for both!). Then, write an if/else statement to determine if the third letter is the same or different for these two variables.

        third_bird = bird[2]
        third_mammal = mammal[2]
   		
        if third_bird == third_mammal:
            print("It's the same")
        else:
            print("It's different")
   

3. Use the method .upper() to print the variable bird as all uppercase. Then, modify this code to redefine the variable bird to be all uppercase. As always, print to confirm!

        ## Just print the uppercase
        print(bird.upper()	third_mammal = mammal[2]
   		
        ## Now redefine
        bird = bird.upper()
   

4. Use the method .count() to count how many r’s are in the variable mammal. Once you have this working, write an if/elif/else statement to check which variable has more r’s. Print informative statements accordingly.

        mammal_r = mammal.count("r")
        bird_r   = bird.count("r")
   		
   		
        if mammal_r > bird_r:
            print("mammal has more")
        elif mammal_r < bird_r:
            print("bird has more")
        else:
            print("same number of r's")	
   

5. Create a new variable called both_animals which contains the contents “SPARROWorangutan”. Make sure to do this entirely with variable names (not with the actual words themselves!!).

   		
        both_animals = bird.upper() + mammal.lower()
   

Part IV: Working with lists

First, define this list variable: numbers = [0, 1, 1, 2, 3, 5, 8, 13].

1. Use indexing to print out the fourth item of the list. Now, use indexing to redefine the fourth element of the list numbers to be -10. Print the list to check.

        ## 4th item = 3rd index!
        index_of_interest = 3 		
   		
        ## just print
        print(numbers[index_of_interest])
   		
        ## now redefine
        numbers[index_of_interest] = -10s
   

2. Use the .index() method to determine which position in the list contains the value 5, and redefine this value as 15.

        which_position = numbers.index(5)
   		
        ## redefine
        numbers[which_position] = 15
   		
        ### Alternatively, all in one go:
        numbers[ numbers.index(5) ] = 15
   

3. Use the .count() method to determine how many items in this list are equal to 1. Use an if statement to print out whether this value is equal to 2 (the correct answer).

        num1 = numbers.count(1)
        correct = 2
   	
        if num1 == correct:
            print("it's 2!")
        else:
            print("it's not 2")		
   

4. Use indexing to the print last two items of the list. Do this in two ways:

   1. Use the len() function to first determine the length of the list, and then print the last two items with this information
   2. Use negative indexing

        ### Solution using len()
        total_length = len(numbers)
        print(numbers[total_length-2 : total_length])
   		
        ### Solution with negative indexing
        print(numbers[-2:=
        num1 = numbers.count(1)
        correct = 2
   	
        if num1 == correct:
            print("it's 2!")
        else:
            print("it's not 2")		
   

5. Create a new variable called original_length which contains the length of the list numbers (use the function len()). Now perform the following tasks, being sure to print after each one!

   1. Use the method .append() to add the new entry 21 to the end of the list numbers.
   2. Create another variable called updated_length which contains the length of numbers after you have appended 21.
   3. Write an if/else statement to check if updated_length is one larger than original_length. Try to incorporate the operator += into your code. Rememeber, you can build this up in stages (i.e. you don’t need to start with += in the first try!).

        original_length = len(numbers)
   		
        ## Append 21
        numbers.append(21)
   		
        ## created updated_length
        updated_length = len(numbers)
   		
        ## compare
        original_length += 1 ## for comparing
        if original_length == updated_length:
            print("append huzzah!")
        else:
            print("append fail")
   

6. Write an if/elif/else statement to compare the sum of the list to the value 50. Use the sum() function, which adds up all items in a list, for this task.

        numsum = sum(numbers)
        compare_to = 50
   		
        if numsum > compare_to:
            print("greater than", compare_to)
        elif numsum < compare_to:
            print("less than", compare_to)
        else:
            print("equal to", compare_to)
   

7. Create a new list: numbers2 = [-4, -8, -12, -16], and append this new list to numbers. This code has created a nested list. Print the final length of the list “numbers”. Did you expect this? Why or why not?

        numbers2 = [-4, -8, -12, -16]
        numbers.append(numbers2)
   		
        print(len(numbers)) ## the appended list creates only 1 more item!
   

8. Finally, determine the length of the final entry in numbers using indexing and the len() function.

        print(len(numbers[-1]))