Difference between new sensor reading and older reading

Hi, I'm trying to measure the difference between the most current sensor reading and a value from 1 second before that. This is so I can then detect whether there are any sudden drops in my temperature and humidity data. I believe the sampling frequency is too high to do the conventional method (present reading-last reading). So if I am taking a reading every 100ms is there a way on Arduino to look at the last 10 readings to obtain a difference over 1 second?

The way I would do this on MATLAB is simply 'sample(index)-sample(index-10)' but I'm not quite sure how I would do it on Arduino IDE.

Any help would be greatly appreciated!

Why not sample every second if that is the interval that you are interested in ?

I was hoping there would be another alternative that would allow for more data to be read

You can certainly read more data then determine the difference over a period of 1 second but what are you going to do with the data that you have read if you read it more frequently ?

If you store readings in a circular buffer you can compare the most recent to a reading N samples back.