Question

Must be a way to avoid doing this in R. Some kind of mapping function? Basically, want to specify a series of grepl conditions and a series of replacements. Thanks,

hold[grepl('TRAVEL', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "TRAVEL"
hold[grepl('IN-KIND:', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "IN-KIND"
hold[grepl('COMPLIANCE', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "COMPLIANCE"
hold[grepl('MEDIA', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "MEDIA"
hold[grepl('WATER|FOOD|OFFICE|Office|CLEANING|ALARM', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "OFFICE"
hold[grepl('DATA', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "DATA"
hold[grepl('LEGAL', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "LEGAL"
hold[grepl('EVENT', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "EVENT"
hold[grepl('CATERING', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "CATERING"
hold[grepl('PHONE', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "PHONE"
hold[grepl('EQUIPMENT', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "EQUIPMENT"
hold[grepl('FUNDRAISING|FINANCE', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "FUNDRAISING"
hold[grepl('PAYROLL', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "PAYROLL"
hold[grepl('LIST RENTAL', hold[, "exp_pur_desc"]), "exp_pur_desc"] <- "LIST RENTAL"

Edit: Yeah, sorry, little flippant. hold is data.frame with one column named “exp_pur_desc.” I can see lapply or sapply working with a “switch” equivalent. Thanks.

Answer 1

Here’s one way:

strReplace <- function(x, mapFrom, mapTo) {
    for (i in seq_along(mapFrom)) {
        x <- gsub(mapFrom[[i]], mapTo[[i]], x)
    }
    x
}

strReplace(c("Hello cruel world!", "Hello again Tellus!"), # Text
           c("Hello", "world|Tellus"), # words to replace (regular expressions)
           c("Hi", "moon"))            # words to replace with
#[1] "Hi cruel moon!" "Hi again moon!"

… so in your case:

hold<-data.frame(ID=11:12, exp_pur_desc=c('FOOD','FINANCE'))
hold[['exp_pur_desc']] <- strReplace(hold[['exp_pur_desc']],
  c('WATER|FOOD|OFFICE|Office|CLEANING|ALARM', 'FUNDRAISING|FINANCE'),
  c('OFFICE', 'FUNDRAISING'))
hold