Explanation
In Excel, empty double quotes ("") mean empty string. The <> symbol is a logical operator that means "not equal to", so the following expression means "A1 is not empty":
=A1<>"" // A1 is not empty
This expression is used four times in the formula shown in the example, in order to test four different cells in a particular order.
The overall structure of this formula is what is called a "nested IF formula". Each IF statement checks a cell to see if it not empty. If not empty, the IF returns the value from that cell. If the cell is empty, the IF statement hands off processing to another IF statement:
=IF(B5<>"",B5,IF(C5<>"",C5,IF(D5<>"",D5,IF(E5<>"",E5,"no value"))))
The flow of a nested IF is easier to visualize if you add line breaks to the formula. Below, line breaks have been added to the formula to line up the IF statements:
=
IF(B5<>"",B5,
IF(C5<>"",C5,
IF(D5<>"",D5,
IF(E5<>"",E5,
"no value"))))
With ISBLANK
Excel contains the ISBLANK function, which returns TRUE when a cell is blank:
=ISBLANK(A1) // A1 is blank
The behavior can be "reversed" by nesting the ISBLANK function inside the NOT function:
=ISBLANK(A1) // A1 is not blank
The formula above can be re-written to use ISBLANK as follows:
=IF(NOT(ISBLANK(B5)),B5,IF(NOT(ISBLANK(C5)),C5,IF(NOT(ISBLANK(D5)),D5,IF(NOT(ISBLANK(E5)),E5,"novalue"))))
