Editing Find and remove duplicates (section)

==== Checking for Duplicate Values in a Specified Range ====
Example function
<pre>
=SUMPRODUCT(COUNTIF(E2:N2, E2:N2)) > COUNTA(E2:N2)
</pre>

This function checks whether there are duplicate values within the range E2 to N2. Here's a breakdown of how it operates:

* COUNTIF(E2:N2, E2:N2): This part counts how many times each value appears in the range. For each cell, it calculates the occurrence count of that value within the entire range.
* SUMPRODUCT(...): Sums all the count results. If there are no duplicates, the sum will equal the number of cells; if duplicates exist, the sum will be greater than the number of cells.
* COUNTA(E2:N2): Counts the number of non-empty cells in the range.
* ... > COUNTA(E2:N2): Compares the sum with the cell count. If the sum is greater, it indicates duplicates exist and the function returns TRUE; otherwise, it returns FALSE.

Alternative methods
* '''Count duplicate occurrences''': Using {{kbd | key = SUMPRODUCT(COUNTIF(E2:N2, E2:N2) - 1)}} to calculate the number of duplicate items
* '''Using UNIQUE function''': Using {{kbd | key = COUNTA(E2:N2) <> COUNTA(UNIQUE(E2:N2))}} as a simplified version (Google Sheets only)

References
* [https://support.google.com/docs/answer/3093991 Google Sheets COUNTIF function]
* [https://support.google.com/docs/answer/3238496?hl=en&sjid=3385137518767327741-NC SUMIFS function - Google Docs Editors Help]
* [https://support.google.com/docs/answer/10522653?hl=en&sjid=3385137518767327741-NC UNIQUE function - Google Docs Editors Help]