R: Find the last dot in a string

Question

In R, is there a better/simpler way than the following of finding the location of the last dot in a string?

x <- \"hello.world.123.456\"
g <- gregexpr(         


        

Answer 1

Does this work for you?

x <- "hello.world.123.456"
g <- regexpr("\\.[^\\.]*$", x)
g

• \. matches a dot
• [^\.] matches everything but a dot
• * specifies that the previous expression (everything but a dot) may occur between 0 and unlimited times
• $ marks the end of the string.

Taking everything together: find a dot that is followed by anything but a dot until the string ends. R requires \ to be escaped, hence \\ in the expression above. See regex101.com to experiment with regex.