Identifier based on conditions-R

Question

I have a database , I am trying to find a identifier with following conditions By taking first 3 letters from first, last 3 letters from last and last 4 digits of Phone1 if Phone1have empty cell we need to take last 4 digits of Phone2

df <- data.frame(first = c("apple", "grape", "rose", "Jasmine", "Apricots", "mango", "banana", "Blueberries"),
                 Last =  c("Jackfruit", "Kiwi", "Mulberry", "rabbit ", "pine", "Limes", "", "Nectarine"),
                 Phone1 = c("1234567890", "(456)7089123", "1230789456", "", "999999", " ", "1112223334", "9998887775"),
                 Phone2 = c("1234737650", "", "15", "8888888888", "99", "3336783245 ", "", "2222222222"))

Expected output:

Answer 1

Does this work:

> library(dplyr)
> df %>% mutate(ID = case_when(Phone2 %in% c('',' ') ~ paste0(substr(first,1,3), substr(Last,1,3),substr(Phone1, nchar(Phone1)-3, nchar(Phone1))),
+         Phone1 %in% c('',' ') ~ paste0(substr(first,1,3), substr(Last,1,3),substr(Phone2, nchar(Phone2)-3, nchar(Phone2))),
+         TRUE ~ paste0(substr(first,1,3), substr(Last,1,3),substr(Phone1, nchar(Phone1)-3, nchar(Phone1)))))
        first      Last       Phone1     Phone2         ID
1       apple Jackfruit   1234567890 1234737650 appJac7890
2       grape      Kiwi (456)7089123            graKiw9123
3        rose  Mulberry   1230789456         15 rosMul9456
4     Jasmine   rabbit               8888888888 Jasrab8888
5    Apricots      pine       999999         99 Aprpin9999
6       mango     Limes              3336783245 manLim3245
7      banana             1112223334               ban3334
8 Blueberries Nectarine   9998887775 2222222222 BluNec7775
>