Adding a column, of which the values depend on whether the value in another column, matches one of f-CodePudding

I have data as follows:

library(stringi)

datfake <- as.data.frame(runif(100, 0, 3000))
names(datfake)[1] <- "Inc"
datfake$type <- sample(LETTERS, 100, replace = TRUE)
datfake$province <- stri_rand_strings(100, 1, "[A-P]")

region_south <- c("A", "B", "C", "D")
region_north <- c("E", "F", "G", "H", "I")
region_east <- c("J", "K", "L")
region_west <- c("M", "N", "O", "P")

I would like to add a column that tells me in which reason each province is. All the solutions I come up with are a bit clunky (for example turning the vector region_south into a two column dataframe, where the second column says south and then merging). What would be the easiest way to do this?

Desired output:

        Inc      type province region
1  297.7387         C        J   east
2 2429.0961         E        D  south

CodePudding user response：

An idea is to use mget to get the regions, unlist and take advantage of the named vector object and match the values with province and return the names, i.e.

v1 <- unlist(mget(ls(.GlobalEnv, pattern = 'region_')))
res <- names(v1)[match(datfake$province, v1)]
gsub('region_(. )[0-9] ','\\1' ,res)


  [1] "north" "east"  "north" "north" "south" "south" "south" "west"  "west"  "east"  "south" "south" "west"  "north" "north" "south" "east"  "north" "south" "east"  "north" "west" 
 [23] "south" "west"  "north" "west"  "east"  "north" "east"  "south" "south" "east"  "south" "west"  "north" "east"  "west"  "south" "south" "east"  "north" "west"  "west"  "south"
 [45] "north" "east"  "south" "west"  "north" "south" "east"  "west"  "north" "north" "north" "south" "north" "south" "north" "north" "west"  "north" "north" "south" "west"  "north"
 [67] "east"  "south" "north" "west"  "south" "west"  "north" "north" "north" "south" "north" "east"  "west"  "south" "west"  "north" "west"  "east"  "north" "west"  "south" "east" 
 [89] "north" "west"  "north" "north" "west"  "south" "west"  "north" "west"  "west"  "south" "west"

CodePudding user response：

We can use case_when along with grepl here:

library(dplyr)
df$region <- case_when(
    grepl(paste0("^[", paste(region_north, collapse=""), "]$"), df$province) ~ "north",
    grepl(paste0("^[", paste(region_south, collapse=""), "]$"), df$province) ~ "south",
    grepl(paste0("^[", paste(region_east, collapse=""), "]$"), df$province) ~ "east",
    grepl(paste0("^[", paste(region_west, collapse=""), "]$"), df$province) ~ "west"
)