stack columns

library(dplyr)
library(tidyr)
dat <- data.frame(id = c('a','b'), item1 = c('香蕉','豆子'),
                  item2 = c('瑪奇朵','山葵'), item3 = c('老虎','蘋果'),
                  stringsAsFactors = FALSE)
dat %>% gather(item,n,-id) %>% arrange(id) %>% select(-item)