I'm a beginner in PureData but would like to create a keyboard-based sampler that, when a key is pressed, it cycles through a bank of samples randomly. For instance, let's say that I play a middle C - what comes out is an endless loop of randomly selected 1/10 of a second clips taken from randomly chosen points inside of samples in a sample bank.

So, let's say I have 3 samples, each 10 seconds long, sitting in a folder somewhere. As soon as a key is triggered, points in those samples are randomly accessed and played for 1/10 of a second, linearly. 1/10 second here, 1/10 second there, etc. If the key is held down, it loops through these samples indefinitely.

I'm not sure if this is possible or not and I'd appreciate any help regarding this idea. Thanks very much.

This is very possible. Check the Help -> Browser -> PureData -> 3.audio.examples and go through the B chapter stuff to get some basics of working with samples. You might also like the sampling chapter of this online book:

http://www.pd-tutorial.com/english/index.html

There's been a number of sample players and such posted on this forum as well, so search around here, too.