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Exercise 2 - Importing Modules

Goals

  • Open, edit, save, and run code
  • Import modules to bring in additional functionality

Preparation

  • Connect your board to the computer and open the code.py file. Delete any pre-existing code from the board. See getting started for help with this step.

Concepts & Vocabulary

  • import
  • module
  • dir()

Background Info

Building on your printing exercise, let's take a look at the board the way the computer sees it.

To complete this exercise, you're going to import the board module and print out the contents of the board. The board module is one we'll use a lot, because it saves us a lot of work. Not all boards are set up the same way - a built in LED might be on pin 12 on one board, pin 13 on another, and pin 4 on a third board. Instead of modifying the code everytime you use a different style of board, you can use board.LED to refer to that pin no matter what microcontroller pin it's actually on.

The dir() function (which stands for directory) will return (not print) a list all the contents of a folder or any other object in Python. Because it returns the list as a value, it can be used as an argument for another function, like the print function.

Try It

Look at the list that is printed out. Can you tell what any of these terms mean?

code 

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import board

print(dir(board))

output 

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Auto-reload is on. Simply save files over USB to run them or enter REPL to disable.
code.py output:
['__class__', '__name__', 'A0', 'A1', 'A2', 'A3', 'GP0', 'GP1', 'GP10', 'GP11', 'GP12', 'GP13', 'GP14', 'GP15', 'GP16', 'GP17', 'GP18', 'GP19', 'GP2', 'GP20', 'GP21', 'GP22', 'GP23', 'GP24', 'GP25', 'GP26', 'GP26_A0', 'GP27', 'GP27_A1', 'GP28', 'GP28_A2', 'GP3', 'GP4', 'GP5', 'GP6', 'GP7', 'GP8', 'GP9', 'LED', 'SMPS_MODE', 'VBUS_SENSE', 'VOLTAGE_MONITOR', 'board_id']

Code done running.

Press any key to enter the REPL. Use CTRL-D to reload.

Show me your code in action

To get credit for this exercise, I will need to see your code running. This will be scored for completion. If I am not available to check your work when you're ready, make sure you use Save As to save a copy on your computer (not only on the board!) so you can continue on and show me the code running later.