Calculate percentile when logical is true

Question

goyanks1989 2016-4-4

评论： Star Strider 2016-4-4

I am looking at a large data set from NASA flight. I am only interested in points when the airplane is higher than 8 km so I set up a logical:

alt8= alt > 8

which gives me back points with 0 (false) or 1 (true) corresponding with points below or above 8 km

Using only these true points when the height is >8, I would like to find the 99th percentile of another data point, vertical velocity.

vv99=prctile(vv,99)

In other words, I need to find the 99th percentile of vertical velocity when alt>8 rather than the 99th percentile for the entire flight.

What kind of loop or statement should I use to extract just the points when alt>8?

Thank you!

Answer 1

Star Strider 2016-4-4

Try this:

vv99=prctile(vv(alt8),99)

goyanks1989 2016-4-4

knew i was overthinking it.... Thank you

Star Strider 2016-4-4

My pleasure.

We all do from time to time.