num = 7
if num % 2 != 0:
    print(f"{num} is odd.")

from machine import PIN means get the PIN class from the file machine from ir_rx.nex import nec_8 means get the NEC_8 class from the file nec in the directory ir_rx

• Use classes!
• Python will not change what I think are global variables in functions.
• If, for example, you have a variable xyzzy, and you reference it in a function, python creates a new one.
• So you have to pass in xyzzy if you want to modify it.
• You then have to return it explicitly, because Python returns the value of the last expression.

    def incrementXyzzy():
       xyzzy = xyzzy + 1
    #does not work because xyzzy is a local created on the fly   

    def incrementXyzzy(xyzzy):
       xyzzy = xyzzy + 1
    #xyzzy is passed in and can be incremented. it will be returned   

    def incrementXyzzy(xyzzy):
       xyzzy = xyzzy + 1
    return xyzzy   #explict return is better
    #xyzzy is passed in and can be incremented. it will be returned   

    xyzzy = incrementXyzzy(xyzzy):

    #the calling function MUST assign the returned value   

• import csv
• file = open('Emp_Info.csv', 'r')
• try:
• reader = csv.reader(file)
• for each_row in reader:
• print(each_row)
• finally:
• file.close()

• create list - stock = []
• append to list - stock.append(“fred”)

• python -m pip install somePackage
• sudo python -m pip install email_to ←—————— does not work

error: externally-managed-environment

This environment is externally managed To install Python packages system-wide, try apt install python3-xyz, where xyz is the package you are trying to install.

If you wish to install a non-Debian-packaged Python package, create a virtual environment using python3 -m venv path/to/venv.

Then use path/to/venv/bin/python and path/to/venv/bin/pip. Make sure you have python3-full installed.

For more information visit http://rptl.io/venv

• open file - input = (“someFileLocation”, “r”)
• read a line - line = input.readline()

file_path = 'randomfile.txt'
file_text = open(file_path, "r")
a = True
while a:
    file_line = file_text.readline()
    if not file_line:
        print("End Of File")
        a = False
file_text.close()

file = open("randomfile.txt", "r")

while (f := file.read()):
    process(f)

file.close()

• packages live in C:\Users\Donald\AppData\Local\Programs\Python\Python313\Lib\site-packages
• a pip install of exifread appeared to work but did not create this package in the above directory
• found it on Git, downloaded a zip, and copied the package to the site-packages directory