Our programs get more interesting if they don’t do exactly the same thing every time they run.
One way to make them more interesting is to get input from the user. Luckily, in Python
there is a built-in function to accomplish this task. It is called
n = input("Please enter your name: ")
The input function allows the programmer to provide a prompt string. In the example above,
it is “Please enter your name: “. When the function is evaluated, the prompt is
shown (in the browser, look for a popup window).
The user of the program can type some text and press
return. When this
happens the text that has been entered is returned from the
and in this case assigned to the variable
n. Run this example a few 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
float converter functions we saw
We often use the word “input” (or, synonymously, argument) to refer to the values that are passed to any function. Do not confuse that with the
input function, which asks the end user of a program to type in a value. Like any function,
input itself takes an input argument and produces an output. The input is a character string that is displayed as a prompt to the user. The output is whatever character string the user types.
Here is a program that turns a number of seconds into more human readable counts of hours,
minutes, and seconds. A call to
input() allows the user to enter the number of seconds.
Then we convert that string to an integer. From there we use the division and modulus
operators to compute the results.
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
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.
Here is a turtle example that asks the user for input on where the turtle should go:
The input functions on lines 5 and 6 ask the user to enter coordinates and saves the resulting strings to the user_x and user_y variables. The statements of lines 8 and 9 convert the strings to integers. On line 11, the turtle draws a line from the center of the window to wherever the user specified.
Check your understanding