Handling ties in multiple grepl statements - r

Question

I'm working on an assignment where I need to clear a lot of messy string data.
I've worked my way with most problems but got stuck with two problems:
Ties when using multiple grepl statements
Lot's of code, that I feel, could be simplified but I can't figure out how
Let's consider this minimal example:
names is a character vector storing names of 3 distinct persons, written in various ways
names should be simplified (recoded) so that multiple occurrences of a person name are stored the same way
Let's assume Johnatan is First John,
Johnnie and johnnie are all Second John,
John, John D., John Doe are Third John.
With my limited R knowledge I came this solution:
names <- c("John", "Johnatan", "Johnnie", "John D.", "John Doe", "johnnie")
names[grepl("johna", names, ignore.case = TRUE)] <- "First John"
names[grepl("johnn", names, ignore.case = TRUE)] <- "Second John"
names[grepl("john d*", names, ignore.case = TRUE)] <- "Third John"
At this point there is john that I have no idea how to recode into Third John as
names[grepl("john", names, ignore.case = TRUE)]
will pick up all the john's in names.
Question:
How can I approach this kind of ties, hopefully in a way, more elegant then what I wrote so far?
Thank you for any hints and suggestions.

Answer 1

You can use a word boundary (\\b) for "john":
names <- c("John", "Johnatan", "Johnnie", "John D.", "John Doe", "johnnie")
names2 = names
names2[grepl("johna", names, ignore.case = TRUE)] <- "First John"
names2[grepl("johnn", names, ignore.case = TRUE)] <- "Second John"
names2[grepl("john(\\b|\\sd.*)", names, ignore.case = TRUE)] <- "Third John"
or with case_when from dplyr:
library(dplyr)
names = case_when(grepl("johna", names, ignore.case = TRUE) ~ "First Join",
grepl("johnn", names, ignore.case = TRUE) ~ "Second Join",
grepl("john(\\b|\\sd.*)", names, ignore.case = TRUE) ~ "Third Join")
Note:
\\b matches a word boundary, which could be either a space or punctuation. for example johnatan would not be matched since john follows another letter a, not a word boundary.
\\s matches a space.
d.* matches d followed by anything (.) zero of more times.
( | ) is a capture group that matches either the left hand side or right hand side of |.
john(\\b|\\sd.*) matches john followed by either a word boundary or a space followed by a d and anything zero or more times. Hence matching "john", "john d.", and "john doe" (ignore.case = TRUE takes care of the cases).
Result:
> names2
[1] "Third John" "First John" "Second John" "Third John" "Third John" "Second John"

Answer 2

temp = c(Johnatan = "First John", johnnie = "Second John", John = "Third John")
temp[apply(X = sapply(names(temp),
function(x) grepl(pattern = x,
x = names,
ignore.case = TRUE)),
MARGIN = 1,
FUN = function(x) head(which(x), 1))]
# John Johnatan johnnie John John johnnie
# "Third John" "First John" "Second John" "Third John" "Third John" "Second John"