concatenate 2 columns into one and display as list in a different cell

Question

I have two columns A and B with for example:

A     B
aa    1
bb    2
cc    3
dd    4 

I want another cell in the sheet to be a list of the concatenate of them so C3 will be: aa 1, bb 2, cc 3, dd 4

That is for instance for a single row CONCATENATE(A1 & " " & B1).

How do I do it for this and display as a list?

Answer 1

To use the concatenated output as list input for a data validation:

Presuming you have concatenated list in column c starting from C2;

Step 1: Create a named range and enter this formula in the Refers to: field; =Sheet1!$C$2:INDEX(Sheet1!$C$2:$C$1000,COUNTA(Sheet1!$C$2:$C$1000))

Step 2: Use the name created as input in the data validation:

Answer 2

try =concatenate(A1," ",B1,",",A2," ",B1,",")