Why does this work?

[eberaud]

I was shocked to see that LabVIEW manages to execute this code properly. Can anybody explain why it works? Aren't clusters and arrays 2 different things?

[drjdpowell]

A cluster is a fixed-size array.  I often use this to convert clusters (of mixed types) into an Array of Variants.

[hooovahh]

21 minutes ago, drjdpowell said:

A cluster is a fixed-size array.  I often use this to convert clusters (of mixed types) into an Array of Variants.

I use this feature all the time to make code more reusable, being able to find all labels, data types, and values of each element in a cluster quite easily.  It's getting back that can be more tricky, where you need to take the array of variants, turn it into a cluster (using the array to cluster setting the size correctly) then a variant to data going from the variant to the cluster.  I made an XNode for it a while ago that just sets the cluster size as you wire it up.

[eberaud]

Uhm, If I reall y want/need to understand this I guess I need to dig into type descriptors and so on?

[drjdpowell]

12 hours ago, Manudelavega said:

Uhm, If I reall y want/need to understand this I guess I need to dig into type descriptors and so on?

Type descriptors?  No.   There are VIs such as  “Get Type Information.vi”, which give you the info.

Type descriptors come with flattening data, and flattening/unflattening data is slow.  The various Variant functions are much faster.  

Edited January 12, 2017 by drjdpowell

[eberaud]

Thanks for all those answers!