How to combine multiple consecutive ISBLANK checks in Google Sheets?

Question

I want to check cells and combinations of cells, whether they are empty, and after check write values into them. But there are multiple checks - i struggle with deeply nesting syntax. It should look like:

• First check: =IF(ISBLANK(A2),B2,A2)
• Second check: IF ISBLANK(A2) AND ISBLANK(B2) → C2
• Third check: IF ISBLANK(A2) AND ISBLANK(B2) AND ISBLANK(C2) → D2

How can i combine all these checks in this order into one arrayformula?

Answer 1

To expand on Calculuswhiz comment -

I use to have the same problem, but found out you can write formulas in code structure. It really helped me keep track of what was going on:

This formula cascades through the checks, so you don't need to use the AND. If the first if statement is blank, then check the second if statement, if both are blank, check the third, etc

Answer 2

Try:

=if(len(A2&B2&D2),"something","something for empty cells")

When all cells are empty then sum of these cells is empty too.