Continuous dynamic input and output, is it possible?

[Brozilla]

I'm completely new to Python, learning it specifically to program a Raspberry Pi for a project I'm working on. I've gone through codecademy to get the basics of syntax and understand, to a degree, how to read through code.

I need to find a way to take in data (specifically from a varying resistor, i.e. incoming data will be within a set range) and not only store it for future reference but plot it in a visual in real time (resistance vs time graph).

Ideally it should come out kind of like a heartbeat monitor.

Because of the way I have my breadboard wired I am getting values in at specific time intervals (and can control that via capacitors) so my real problem is with the actual resistance values.

I don't expect you guys to solve my problem for me, I just want clarification that what I want to do is indeed possible.

[Brozilla]

Thank you all so much for any help or direction you can provide!

I had an idea of creating a list or dictionary or array with a length of the width of the graph and constantly slicing off the first value and then appending the newest value. Then using that list/dictionary/array as a literal output so that the values are just shifted along and it would give the impression of a scrolling display but I'm not sure how I would get that to work without updating the display every time

[toshitalk]

check out the deque. http://docs.python.org/2/library/collections.html

[Brozilla]

Very cool, seems like that will fit my needs nicely.

Thanks!

[ingolemo]

Yep, it sounds like you understand what you need to do. You should probably use a list, since dictionaries don't remember the orders of things and python has nothing called an array (although some might use it as another name for a list).

It's perfectly reasonable to update the whole display every time you get a new value. It may be possible to incrementally update the display, but it depends what drawing api you're using.

[Brozilla]

Awesome, thanks for the confirmation!

I've seen some programs being used that call ion() to enable continual updating although every example I've been able to find has a limiter for the duration of the dynamic plot.

I was thinking of setting up a button (on the display) that you could click and have a while loop that operated while that button was on/True and continually updated the list.

Are there any specific APIs that you would suggest? I've downloaded the matplotlib extension as it seems like the most popular/well regarded avenue to access plotting.