Computer Science for STEM The PreTeXt Interactive Edition

The program in the previous section works fine but is very limited in that it only works with one value for total_secs. What if we wanted to rewrite the program so that it was more general. One thing we could do is allow the user to enter any value they wish for the number of seconds. The program could then print the proper result for that starting value.

In order to do this, we need a way to get input from the user. Luckily, in Python there is a built-in function to accomplish this task. As you might expect, it is called input.

n = input("Please enter your name: ")

The input function allows the user to provide a prompt string. When the function is evaluated, the prompt is shown. The user of the program can enter the name and press return. When this happens the text that has been entered is returned from the input function, and in this case assigned to the variable n. Make sure you run this example a number of times and try some different names in the input box that appears.

It is very important to note that the input function returns a string value. Even if you asked the user to enter their age, you would get back a string like "17". It would be your job, as the programmer, to convert that string into an int or a float, using the int or float converter functions we saw earlier.

To modify our previous program, we will add an input statement to allow the user to enter the number of seconds. Then we will convert that string to an integer. From there the process is the same as before. To complete the example, we will print some appropriate output.

The variable str_seconds will refer to the string that is entered by the user. As we said above, even though this string may be 7684, it is still a string and not a number. To convert it to an integer, we use the int function. The result is referred to by total_secs. Now, each time you run the program, you can enter a new value for the number of seconds to be converted.

Check your understanding

n = input("Please enter your age: ")
# user types in 18
print ( type(n) )

seconds = input("Please enter the number of seconds you wish to convert")
hours = int(seconds) // 3600
total_secs = int(seconds)
secs_still_remaining = total_secs % 3600
print(secs_still_remaining)

seconds = input("Please enter the number of seconds you wish to convert")
hours = int(seconds) // 3600
total_secs = int(seconds)
secs_still_remaining = total_secs % 3600
print(secs_still_remaining)