Rename duplicates with random alphabets in a column - Excel

Question

I have a list of 500 names in column A.

1  name1
2  name2
3  name3
4  name1
5  name2
6  name3
7  name1
8  name2
9  name3
..

And i need to add a prefix or suffix alphabets to the duplicates. And I should get

1  name1
2  a.name1
3  b.name1
4  name2
5  a.name2
6  b.name2
7  name3
8  a.name3
9  b.name3
..

And i have selected duplicate values

select column -> conditional formatting -> Highlight Cell Rules -> Duplicate Values

How to rename duplicate values with random alphabets prefix or suffix

Answer 1

If you prefer to use a non-random prefix that just contains the next letter, you could do something like this starting in C2:-

=IF(B2=B1,CHAR(96+COUNTIF(B$1:B1,B2))&"."&B1,B2)

I'm assuming that the names are sorted, have a heading and are in column B.

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If you didn't want to sort them, this would still work with a modification:-

=IF(COUNTIF(A$1:A1,A2)>0,CHAR(96+COUNTIF(A$1:A1,A2))&"."&A2,A2)

I'm assuming that the unsorted names are in column A, with a header.