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.
To test IF a value matches a condition, and return one result if TRUE, and another if FALSE.
How to use the VLOOKUP function in Excel
Use functions CHOOSE and RIGHT to create an array of values which includes mixed data types, to feed a LINEST calculation
How to return an array of non-adjacent cells.