merge two columns into one, Part 2

I have a speadsheet with column A and B look like

A     B
NaN     1
1     NaN
2     NaN
NaN     3

Then I want to create a column C

c
1
1
2
3

That is, the value of column C is the value of A if A is nonempty and the value of B if A is empty. Please advise.

Answer 1

[madhan ravi]

nansum([A, B],2)
%or
sum([A, B],2,'omitnan')

[alpedhuez]

What does '2' mean?

[madhan ravi]

Sum along rows

[alpedhuez]

so '2' means rows?

[madhan ravi]

Yes

[alpedhuez]

thank you.