Closed:Convert Cdna To Amino Acid Iteratively 3 Base Pairs At A Time?

Question

[Hmm]

How can i iteratively go through a cDNA sequence in both directions of a genomic location three bases at a time and stop on an amino acid K or an R or maybe miss the first K or R and stop on the next one in both directions.

What is the most efficient way of doing it is? Maybe perl or R or python?

Example image:

Any help is really appreciated. Thanks.