 What I wanted to talk about today in the Circuit Python parsec is how you can filter items in lists. The first thing I have is just I did a file directory list of what is in this directory that's on my feather board sitting right here. So volume circuit pi my files to sort directory. Here's what's in it. I have a bunch of BMP and JPEG files and they have some different names on them. They have things like some of them end in final, some have different version numbers. Sometimes you have a list of files, but you just want to be able to sort of intelligently sort through them and filter for certain tokens, certain pieces of the name. So in this example, what I'm doing is I'm saying just show me things that are JPEG files and just the ones that have that underscore final. So maybe we have a bunch of files on here, but we're only going to do things with the ones that are named final and that happen to be JPEG. Now I can go and change this here. I'm going to say just show me BMP files and I'll resave that and you can see here I'm getting actually two lists. One is just list out all the BMP files so it has filtered out all the ones ending in .JPEG and then I have, you know what, give me the ones that actually have that word final in them and this is this list here at the bottom. I could change that and say I only want to see V1s or V2s or any name token. So the way this works is I'm importing OS and that allows me to do some of these sorting and listing of directories. So I build this list called my files and in it is anything that meets this search. First of all, we list the directory, then we make all the names lowercase, make life easier on us. And then we're doing our first filter here, which is if the file name ends with and then it has to be . and my suffix, in this case BMP, and it doesn't start with a . because sometimes we get these . files so I don't want any of those. So that's what prints my first list out. Then I can take that list and refine it, filter it even further. So then I take that list and I say for each of the items in that my files list, go ahead and tell me any of them that find, so filename.find, this string right here underscore final. If it includes that, then I add that to a new list and then I'm printing each of those items out and then we can go and do further things like display all the JPEGs, display all the BMPs, do stuff with wave files, only things with a certain version number or final in them. And so that is how you can do list filtering in CircuitPython and that is your CircuitPython Parsec.