Excel IFERROR function
Excel’s IFERROR function traps errors that could be returned from a formula or calculation, and gives you control over what is returned instead of an error message.
Excel Function
Excel IF function
To test IF a value matches a condition, and return one result if TRUE, and another if FALSE.
VLOOKUP Excel function – explanation and examples
How to use the VLOOKUP function in Excel
CHOOSE function with LINEST
Use functions CHOOSE and RIGHT to create an array of values which includes mixed data types, to feed a LINEST calculation
CHOOSE function with array
How to return an array of non-adjacent cells.