regex - R: How to replace . in a string?

Question

I have a string say "a.b" and I want to replace "." with "_".

gsub(".","_","a.b")

doesn't work as . matches all characters.

gsub(".","_","a.b")

Just gives me an error.

Reading the documentation on ?gsub is not that helpful!

So how to do this straight-forward thing?

Answer 1

. matches any character. Escape . using to match . literally.

itself is also should be escaped:

> gsub("\.", "_", "a.b")
[1] "a_b"