how to replace value in a string based on value in another column in excel

Question

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I want to replace the 'AA' in column B with corresponding values in Column A. How can I achieve that. I am looking for following results:

Column A
Bill
Invoice

Column B
ABAACD EFAAGH
ABAACD EFAAGH


Result
ABBILLCD EFBILLGH
ABINVOICECD EFINVOICEGH

Answer 1

In cell C1 use this formula and copy it down:

=SUBSTITUTE(B1,"AA",A1)

Check out the SUBSTITUTE function for more information.

_{This answer was originally posted as a comment by @tigeravatar: feel free to repost this answer as your own, and leave me a comment so I'll delete this copy. This kind of answer has been stipulated for questions with no answers, but issue solved in the comments .}