How do I concatenate data from multiple columns on one sheet into a single column on another sheet?

Question

I need to take separate columns containing first and last names on one spreadsheet, and combine them into a single column on a different sheet. Right now my formula is

=CONCATENATE(IMPORTRANGE("URL", "A1:A3"), " ", IMPORTRANGE("URL", "B1:B3"))

What I would want is to get a single column of

First1 Last1  
First2 Last2  
First3 Last3

But instead I am getting

First1First2First3 Last1Last2Last3

Because the second argument in the IMPORTRANGE function is a string, I can't just direct it to one cell and then drag the function over multiple cells like I normally would when concatenating. Is there a way to accomplish what I want without copying multiple data sets into one spreadsheet and working from there?

Answer 1

This can be done with an arrayformula as follows:

=arrayformula(importrange("URL", "A1:A3") & " " & importrange("URL", "B1:B3"))

The inner part describes what should be done within one row; the arrayformula then says "do it for every row".