# Check if value exists in another column of a Microsoft Excel document

Today I spent some time looking for this trick. The function to use is called `VLOOKUP`

. From Office Support web page:

Use VLOOKUP, one of the lookup and reference functions, when you need to find things in a table or a range by row. For example, look up a price of an automotive part by the part number.

Function `VLOOKUP`

requires 4 arguments. the first two are easy to understand, but the third

- The value to look for.
- The range where we want to look for the value.
- Index of the column in the range containing the return value.
- [optional] TRUE for approximate match and FALSE for a perfect match.

Let’s see an example for argument 3, from the same Office Support site:

For example, if you specify

`B2:D11`

as the range, you should count B as the first column, C as the second, and so on.

So, this means that given a range of a single column (aka. `B2:B2550`

) this argument will be `1`

. If the range includes more that one column, then it should take the index of the value to return.

The following is an example of using `VLOOKUP`

to find the *value* of an *item*:

In my case I want to get a typical boolean `TRUE`

/ `FALSE`

to know if the value to look for is in a given column or not. To this end I used two more functions: `IF`

and `ISERROR`

.

The following picture shows the use of `VLOOKUP`

to check if the elements in column `A`

are in column `C`

using the 4Th argument of `VLOOKUP`

, set to `FALSE`

:

As can be see, when an element from `A`

is not present in the `C`

it returns `#N/A`

(aka. an error). So we can use `ISERROR`

to check if `VLOOKUP`

raises an error and `IF`

to return `TRUE`

or `FALSE`

:

The final formula follows:

```
=IF(ISERROR(VLOOKUP(A2,C2:C7, 1, FALSE)), FALSE, TRUE)
```