Array Split / Replace Subarrays

[Achtu]

I have a 2D array and I would like to replace the eleventh column with the lowercase of the fifth column. I understand that it is recommended to use Array Split / Replace Subarrays and my question is, am I using it correctly? And is there any other way? Thanks in advance.

Question.vi

[Mads]

You do it right yes, but just use the method you used at the bottom. It is more simple and just as "in-place" as the top-method. 

If the number of rows were huge and you mainly needed to save memory it might make sense to convert and replace one element at a time instead (avoiding a full copy of the column to be converted, which you still have in your two solutions (verified quickly using ArrayMemInfo...)), but that would be a different code.