How to access non-sequential array indices

[ptc-5071035]

Sorry if this has been answered before. I have looked around for the last hour or two and can not seem to find anything about this. I've created my own function to solve this issue, but I can't help but think that it should be easier.

I would like to access an array with another array of indices. Unlike a range, these indices are non-sequential. When I try to access the array just like a range would, it says that the value must be an integer. I've also tried vectorizing it, to no avail.

Any insight you guys might have would be greatly appreciated. I'm using Mathcad Prime 2.0, by the way.

[Werner_E · Accepted solution]

What do you mean by "access" the first array? Selecting a subset of data values in the first vector given by another array of indices?

If yes, here are two possible solutions:

[ptc-5071035]

That's exactly what I was looking for! Thank you!

[Werner_E]

You are welcome.

Here is a third way using a local function and vectorization: