I have a question about replacing specific characters in a string based on their position in the string.

For example, I have

atcgcgtacatcgatac

and I want to make the ninth character from the left upper-case instead of lower-case, i.e., it should look like

atcgcgtaCatcgatac

after I am done. Furthermore, I have many sequences and various positions for each sequence where the casing of letters needs to be changed. How might I do this?

P.S. I have tried substr, but I can't fit my parameters into the arguments.

In reply to String character replacement based on position by shu_uemura

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