Python Projects for Beginners a ten-Week Bootcamp Approach to Python Programming

Step #1: Ask User for Calculation to Be Performed

For each one of these steps, let’s put the code in separate cells. This will allow us to section of the specific steps for our project, making it easier to test each step. The first step is to ask the user to input the mathematical operation to be performed (add, subtract, etc.):

# step 1: ask user for calculation to be performed
operation = input("Would you like to add/subtract/multiply/divide? ").lower( ) print( "You chose { }.".format(operation) ) # for testing purposes

Go ahead and run that cell. Depending on what the user inputs, your output will print what they chose. You’ll notice that on the line where we accept the input, we also convert it to lowercase right away. This is to avoid case-sensitive issues later. Our print statement is simply for testing purposes on this cell only and will be removed later.

Step #2: Ask for Numbers, Alert Order Matters

In the cell below step #1, we’ll need to create the next step of our logic. Here, we ask the user to input a couple of numbers and output those numbers for testing purposes:

# step 2: ask for numbers, alert order matters for subtracting and dividing if operation == "subtract" or operation == "divide": print( "You chose { }.".format(operation) ) print("Please keep in mind that the order of your numbers matter.") num1 = input("What is the first number? ") num2 = input("What is the second number? ") print( "First Number: { }".format(num1) ) # for testing purposes print( "Second Number: { }".format(num2) ) # for testing purposes

Go ahead and run that cell. Notice that we put in a print statement alerting the user that if they chose subtraction or division, the order of numbers matters. This is important as num1 will always be on the left side of the operator (in our program), which makes a huge difference.
Note rerun the previous cell if you get an error for undefined.