Writing Your Own Module

Any Python file can be imported to another Python file using the import command, which means that every Python file we’ve made in this class can be used as a module.

Let’s create a module out of yesterday’s program. Create a new Python file called lesson5-2.py. In the first line, type the command import followed by the filename without the .py extension. So if yesterday’s file was called yesterday.py, enter import yesterday. This line lets us now use all the functions from yesterday’s file in our new file.

# lesson5-2.py

import yesterday

One of the functions we wrote yesterday was called circumference() and we passed in the single parameter of a radius. To use this function in our new file, when we make a function call, we have to include the module name since the circumference() function is not defined inside our current file:

# lesson5-2.py

import yesterday

print(yesterday.circumference(2))

We can call any of the functions in yesterday.py in a similar way. Here is a function call to the card() function (which doesn’t need any parameters):

# lesson5-2.py

import yesterday

print(yesterday.circumference(2))
print(yesterday.card())

Homework:

  1. Read HTCS, 5.5
  2. Write a Python program with 1) a function that calculates the area of a circle, 2) a function that calculates the circumference of a circle, and 3) uses the math module to define a variable pi with a more accurate value than just 3.1415.
  3. Create a second Python program that imports your first Python program as a module. Then write a function call for both of the functions you wrote in the first program. Add a print statement to print a more accurate value of pi.
  4. Submit both files to the Petra Portal.