 Let's discuss the print function in Python. I'm going to write a program in the upper half of the Thani window. Whenever I write a program, I always start off with comments that give a short description of the program, and then my name and date, and then the purpose of the program. Namely, given an age in years, calculate the approximate age in days. I'll want a variable to hold the number of years. I'll call it years, and set it to 27. Then I'm going to calculate the total number of days, and that's going to be set to 365 times the number of years. And then, finally, I'll print the number of days. This is the simplest form of the print function. You give it a single thing to print, in this case, a variable. Let's save that program. I'm using Linux, by the way, so if you're using Windows or macOS, your saved dialog might not look anything like this. We'll name this program age.py, and save it. When we run the program, we get the number 9855. The program works, but it's not ideal. If I give this program to someone else and they run it, all they'll see is a number with no explanation of what the number means. Whenever you print something, you really want to label it, so the people who are using your program will know what it is that you've printed. Python's print function can print as many things as you want if you separate them by commas. That means I can print the words your age of, and then the number of years, which is in the variable years. The words is about, the number of days from that variable, and the word days followed by a period to end the sentence. Let's run the program again. By the way, in Thawne, when you run a program, it will automatically save it for you. And now we get some output that's much more meaningful. We needed a lot of commas and quote marks to make this work. Wouldn't it be nice if there were a more compact way to do this output? There is such a way, and it uses something called F-strings, where the letter F stands for formatted. We're going to put the letter F before the opening quote mark of our string. We're going to start the text as usual, your age of, but now when I want the value of a variable, I put its name in braces. Then I continue with my text. I need the variable days, and I put it in braces also, and then the word days, period, and close my quote marks. And now when I run the program, I get the exact same output, with a lot less trouble. F-strings are really powerful. You can do a lot of wonderful things with them. Here's another program. In this program, I want to calculate the money saved. Again, I'll follow it with my name and date. And the long description of the program is, given a price and a discount percentage, what is the amount of money I save? Well, let's say my amount becomes $19.95, and my percentage is 7.5%. The amount I save is going to be the percentage, divided by 100, multiplied by the amount. I can print that out using an F-string. Again, start with the F and the quote mark. I want whatever is in my percentage variable, followed by a percent sign of, and then the original amount is the amount saved. Since this is a new file, we'll have to save it, and we'll call it savings.py. When we run it, we get output, but that last number isn't very beautiful. When working with monetary amounts, we want to always have two digits to the right of the decimal point. F-strings will let us do this. In order to make it work, we need to add something to our formatting string for the saved variable. After the name of the variable, put a colon. This tells Python some special formatting information is coming up. Then, a decimal point to say that you want decimal places formatted, a two to tell how many places should go to the right of the decimal point, and an F to say this is a float value. Now, when you run the program again, you get two decimal places, and Python has rounded the value up for you. For the sake of completeness, let's make sure that the amount always has two decimal places by putting the colon.2f, and let's always display the percentage with three places to the right of the decimal, colon, decimal, three places, floating point. When we run the program again, we get the percentages and monetary amounts with exactly the number of decimal places that we want. And that's a quick overview of the print function and the wonderfulness of F-strings.