Arrays are stored in memory as one continuous block of data. Using build array adds to the data. So LabVIEW must shuffle around in memory looking for a block of empty memory large enough to hold the new array. Do this too many times or with very large datasets you run into problems.
Array subset means take a section of the array. For example one row, or one column, or one 2-D array portion of a larger 2-D array. It's a bit different than Index array because index array only returns 1 row or 1 column of a 2-D array, or 1 element of a 1-D or 2-D array. You can do the same with array subset, but array subset is more flexible in the amount of data and its shape that it can return.
It does not really split data. There is a 1-D split array function, which splits a 1-D array into two separate 1-D arrays. Array subset only returns one portion of an array.
I recommend looking at context help (turned on with Ctrl-H) and look at the help for each of the functions and compare them.
Message Edited by Ravens Fan on 01-13-2009 08:59 PM
