Count dots on any number of black and white cards as one input (using a loop)

• Make variables called:

  • total_number_of_dots and set its value to 0.
  • number_of_dots and set its value to 1. You will need to multiply number_of_dots by 2 each time you go through the loop
  • cards and set its value to the string entered as the input. Check each letter of the input string cards (use a loop to iterate the number of letters in the input) starting from the last letter. If it’s ‘W’ add the corresponding number of dots (1 for the last letter, 2 for the second to last letter and so on) to the total number of dots. Display the total_number_of_dots as the output.
  • i and set its value to the number of letters in the input minus 1. Use this variable to access a letter at the i position in the string.

• You can access a letter at the specified position in a string by using brackets, like cards[i]

• In this challenge you need to access all the letters in user’s input and check to see if each of them is equal to B (black) or W (white).

• You can find how many letters a string has by using len(cards)

• In this challenge you need to check if each letter of the input is equal to ‘W’ or `B’ using and if statement

Print statements

# Print a string directly
print("Hello World!")

# Print a variable
print(my_var)

Variables

# Set a variable as a string
fruit_name = "Apple"

# Set a variable as an integer 
pieces_of_fruit = 7

# Set a variable from a calculation
cost_of_fruit = pieces_of_fruit * cost_per_item

# Add one to a value
pieces_of_fruit += 1

Conditionals

# Find out the discount on fruit
if pieces_of_fruit > 100:
   print("Bulk discount applies")
elif pieces_of_fruit > 5:
   print("Discount applies")
else:
   print("No discount")

For loops

# Print numbers 0-9 - remember Python starts counting from 0 
for num in range(10):
    print(num)

While loops

# Print numbers 0-9 using a while loop and a variable
num = 0
while num < 10:
    print(num)

    # Increment the variable by one.
    # It will prevent an infinite loop!
    num += 1 

Lists

# Create a list of fruit 
fruit = ["Apple", "Banana", "Orange", "Pear"]

Functions

# Create a function which prints a greeting
def greeting(name):
    print("Hello " + name)

# Call the function
greeting("Spiderman")