.pick.category <- function() {

## This function prompts a menu for selecting a search category and returns
## the corresponding 3-letter code used by Craigslist

   categories <- read.table(textConnection("

    CODE = DESCRIPTION

    sss = all for sale / wanted
    ata = antiques
    ppa = appliances
    ara = arts+crafts
    pta = auto parts
    baa = baby+kids
    bar = barter
    haa = beauty+health
    bia = bikes
    boo = boats
    bka = books
    bfa = business
    cta = cars+trucks
    ema = cd/dvd/vhs
    moa = cell phones
    cla = clothing+accessories
    cba = collectibles
    sya = computers
    ela = electronics
    gra = farm+garden
    zip = free stuff
    fua = furniture
    gms = garage sales
    foa = general for sale
    hsa = household
    wan = items wanted
    jwa = jewelry
    maa = materials
    mca = motorcycles
    msa = musical instruments
    pha = photo+video
    rva = recreational vehicles
    sga = sporting goods
    tia = tickets
    tla = tools
    taa = toys+games
    vga = video gaming"), header = TRUE, sep = "=", strip.white = TRUE,
                          stringsAsFactors = FALSE)

   selected.idx <- menu(categories$DESCRIPTION, title = "pick a category:")

   return(categories$CODE[selected.idx])
}