Usng R - gsub using code in replacement - Replace comma with full stop after pattern-CodePudding

I would like to manually correct a record by using R. Last name and first name should always be separated by a comma.

names <- c("ADAM, Smith J.", "JOHNSON. Richard", "BROWN, Wilhelm K.", "DAVIS, Daniel")

Sometimes, however, a full stop has crept in as a separator, as in the case of "JOHNSON. Richard". I would like to do this automatically. Since the last name is always at the beginning of the line, I can simply access it via sub:

sub("^[[:upper:]] \\.","^[[:upper:]] \\,",names)

However, I cannot use a function for the replacement that specifically replaces the full stop with a comma.

Is there a way to insert a function into the replacement that does this for me?

CodePudding user response：

Your sub is mostly correct, but you'll need a capture group (the brackets and backreference \\1) for the replacement.

test_names <- c("ADAM, Smith J.", "JOHNSON. Richard", "BROWN, Wilhelm K.", "DAVIS, Daniel")

sub("^([[:upper:]] )\\.","\\1\\,",test_names)
[1] "ADAM, Smith J."    "JOHNSON, Richard"  "BROWN, Wilhelm K."
[4] "DAVIS, Daniel"

CodePudding user response：

Can be done by a function like so:

names <- c("ADAM, Smith", "JOHNSON. Richard", "BROWN, Wilhelm", "DAVIS, Daniel")

replacedots <- function(mystring) {
  gsub("\\.", ",", names)
}
replacedots(names)
[1] "ADAM, Smith"      "JOHNSON, Richard" "BROWN, Wilhelm"   "DAVIS, Daniel"