loops.md

Basics:

1. What is an efficient way to run the command puts "hello" five times?

2. If you're looping through an array, what method should you probably use?

3. What would be the output of the following loop?

   4.times do |count|
     puts count
   end
   

4. If you want to produce the following output:

   1
   2
   3
   4
   

   How could you edit the following script?

   4.times do |count|
     puts count
   end
   

5. What is wrong with the following script?

   staff = ['kelsey', 'arvin', 'vince', 'dave', 'darby']
   
   staff.times do |name|
     puts name
   end
   

6. What could be improved in the following script?

   seasons = ['spring', 'summer', 'fall', 'winter']
   seasons.each |count|
     puts count
   end
   

7. If you wanted to produce the following output:

   hello 0
   hello 1
   hello 2
   hello 3
   hello 4
   

   How could you edit the following script?

   5.times do
     puts 'hello'
   end
   

8. Explain how the block variable is getting set in the following script

   4.times do |block_var|
     puts block_var
   end
   

9. What is the difference between the block variables in the following two loops?

   languages =['English', 'Spanish', 'Chinese', 'Tamil', 'Russian']
   5.times do |block_var|
     puts block_var
   end
   

   languages =['English', 'Spanish', 'Chinese', 'Tamil', 'Russian']
   languages.each do |block_var|
     puts block_var
   end
   

10. If you're looping through the following array using .each, what would you name block_var? Why?

    colors_array = ['red', 'blue', 'green', 'orange']
    colors\_array.each do |block_var|
      puts block_var
    end
    

11. How could you make the following code more efficient?

    count = 0
    5.times do
      puts count
      count += 1
    end
    

12. Specify the state of each variable at the end of each line each time through the loop.

    ex)

    Loop 1:
    line 1: x = 3, y = 5
    line 2: x = 3, y = 7
    line 3: x = 3, y = 9
    
    Loop 2:
    line 1: x = 4, y = 5
    line 2: x = 4, y = 7
    line 3: x = 4, y = 9
    

    size = 5
    count = 0
    3.times do
      puts "Count: #{count} and Size: #{size}"
      count = count + 1
    end
    

13. Will the final puts command work in the following script? Why or why not?

    5.times do
      x = 3
      puts x
    end
    
    puts x
    

14. Will the final puts command work in the following script? Why or why not?

    x = 0
    5.times do
      x = 3
      puts x
    end
    
    puts x
    

Good to know:

1. What are the values of each variable other than item_price_array in the following loop at:

   a) the end of the third line of the loop, during round 3?

   b) the end of the first line of the loop, during round 4?

   item\_price_array = [10, 20, 100, 50]  # 11, 11/ 22, 33/ 110, 143/ 55, 143
   sales_tax = 0.1
   total = 0
   
   item\_price\_array.each do |item_price|
     subtotal = item\_price + item\_price * sales_tax
     total = total + subtotal
     puts "Your total so far is #{total}"
   end
   

2. Create at least 3 different loops to produce the following output using colors_array

   output:

   red
   blue
   green
   orange
   

   colors_array = ['red', 'blue', 'green', 'orange']
   

3. How could you refactor(improve) the following script?

   staff = ['kelsey', 'arvin', 'vince', 'dave', 'darby']
   
   count = 0
   staff.each do |staff_member|
      puts "#{staff_member} is number #{count} in the list"
      count = count + 1
   end
   

4. Specify the state of each variable at the end of each line each time through the loop. Also specify what prints to the screen every loop.

   x = 0
   4.times do |count|
     x += 1
     count = count + 1
     x = 4
     puts count
   end