=CHOOSE(index_num, value1, [value2], ...)
=CHOOSE(2,"red","blue","green") // returns "blue"
In this example, the CHOOSE function has an index number of 2, meaning it returns "blue", the second value listed.
=CHOOSE(3,"red","blue","green") // returns "green"
In this example, the index number in the CHOOSE function is 3, meaning it returns "green", the third value listed.
=CHOOSE(B5,"red","blue","green") // returns "red"
In this example, the CHOOSE function has an index number specified by the cell B5. Because B5=1, the CHOOSE function returns the first value listed, which is "red".
The CHOOSE function selects a value from a list of up to 254 value arguments using an index number.