How to find index of nearest value in array

[OnlyOne]

Hello,

i have a double-array A and a double value B.

How can i find out which number in the array A is the nearest number to the number B?

Thanks for help

[Taki1999]

There's a few different ways to do this. The most efficient will depend on the properties of array A.

Is array A sorted? If so, I think a threshold and final compare will be your best bet.

If not, you can brute force it by calculating a distance array and taking the min value from there.

[OnlyOne]

The array-size is only 10 values.

How do i calculate a distance -array?

[Taki1999]

I guess I'd do this as a distance squared array.

distance squared array = (A-B)^2

Then do a Min-Max on the distance squared array to find the index of minimum distance. That index on your A array is the closest numeric value to B.

With just 10 values, your other alternative would be to sort A, then do a threshold of A using B to find the transition index. Compare either side to find the minimum.

[Hooovahh]

You aren't giving many details, or answering the questions already asked.  But still I think this is easy enough.  As mentioned if the arrays are sorted you can probably optimize it.

[OnlyOne]

Thanks you for trhe example.

My B is only a value, not array. Only A is an array.

[GerdW]

Hi One,

you already have more than 700 messages in the forum so I guess you already left the "absolute beginner" status (regarding LabVIEW) behind you.

But still you are not able to calculate the minimal difference of an array and a scalar number?

[paul_cardinale · Accepted solution]

If the array is sorted, the built in function "Threshold 1D Array" might work for you.