The INDEX Function is categorized under Excel Lookup and Reference functions. The function will return the value at a given position in a range or array. The INDEX function is often used with the MATCH function. We can say it is an alternative way to do VLOOKUP.
As a financial analyst, INDEX can be used in other forms of analysis besides looking up a value in a list or table. In financial analysis, we can use it along with other functions, for lookup and to return the sum of a column.
There are two formats for the INDEX function:
The Array Format of the INDEX Function
The array format is used when we wish to return the value of a specified cell or array of cells.
=INDEX(array, row_num, [col_num])
The function uses the following arguments:
Array (required argument) – This is the specified array or range of cells.
Row_num (required argument) – Denotes the row number of the specified array. When the argument is set to zero or blank, it will default to all rows in the array provided.
Col_num (optional argument) – This denotes the column number of the specified array. When this argument is set to zero or blank, it will default to all rows in the array provided.
The Reference Format of the INDEX Function
The reference format is used when we wish to return the reference of the cell at the intersection of row_num and col_num.
Reference (required argument) – This is a reference to one or more cells. If we input multiple areas directly into the function, individual areas should be separated by commas and surrounded by brackets. Such as (A1:B2, C3:D4), etc.
Row_num (required argument) – Denotes the row number of a specified area. When the argument is set to zero or blank, it will default to all rows in the array provided.
Col_num (optional argument) – This denotes the column number of the specified array. When the argument is set to zero or blank, it will default to all rows in the array provided.
Area_num (optional argument) – If the reference is supplied as multiple ranges, area_num indicates which range to use. Areas are numbered by the order they are specified.
If the area_num argument is omitted, it defaults to the value 1 (i.e., the reference is taken from the first area in the supplied range).
How to Use the INDEX Function in Excel
To understand the uses of the function, let us consider a few examples:
We are given the following data and we wish to match the location of a value.
In the table above, we wish to see the distance covered by William. The formula to use will be:
We get the result below:
Now let’s see how to use the MATCH and INDEX functions at the same time. Suppose we are given the following data:
Suppose we wish to find out Georgia’s rank in the Ease of Doing Business category. We will use the following formula:
Here, the MATCH function will look up for Georgia and return number 10 as Georgia is 10 on the list. The INDEX function takes “10” in the second parameter (row_num), which indicates which row we wish to return a value from and turns into a simple =INDEX($C$2:$C$11,3).
We get the result below:
Things to Remember
#VALUE! error – Occurs when any of the given row_num, col_num or area_num arguments are non-numeric.
#REF! error – Occurs due to either of the following reasons:
The given row_num argument is greater than the number of rows in the given range;
The given [col_num] argument is greater than the number of columns in the range provided; or
The given [area_num] argument is more than the number of areas in the supplied range.
VLOOKUP vs. INDEX function
Excel VLOOKUP is unable to look to its left, meaning that our lookup value should always reside in the left-most column of the lookup range. This is not the case with the INDEX and MATCH functions.
VLOOKUP formulas get broken or return incorrect results when a new column is deleted from or added to a lookup table. With INDEX and MATCH, we can delete or insert new columns in a lookup table without distorting the results.