Adding character to a column in data frame

Question

Is there a way to add "." at the end of each cell of a column? something similar to : Add characters to a numeric column in dataframe but at the end of the value.

Answer 1

With paste, it is easier

df1$V1 <- paste0(df1$V1, ".")

Or using sprintf

df1$V1 <- sprintf("%s.", df1$V1)

Answer 2

You can use regex and sub and backreference:

a <- c("abc", "dfg", "hij", "xyz")
sub("^(.*)$", "\\1.", a)
[1] "abc." "dfg." "hij." "xyz."