Let's say I have an array with 100 string elements. Now I have to
check if a particular string is same as one of the elements in the
array, is there a simple way of doing so instead of using many
If/Elseif statements?

If not, I suppose one would have to use some kind of lookup functions.
In that case, does it necessarily mean one would have to include a
data worksheet (invisible or otherwise) in the file for the lookup?

For example, there are 100 string elements in column H. I then create
the newArray by applying various left/mid/right functions to column H.
How do I check if strVariable is same as one of the elements in
newArray? Do I have to list all the elements of newArray on a data
worksheet first?

TIA