3.4 Case Statement

20200421 Many languages support a case or switch statement. R did not originally have a case statement but it was introduced through tidyr as dplyr::case_when():

library(dplyr)

with(ds %>% sample_n(100),
     case_when(max_temp > 35 ~ "hot",
               max_temp > 25 ~ "warm",
               max_temp > 18 ~ "mild",
               max_temp > 12 ~ "cool",
               max_temp >  0 ~ "cold",
               TRUE          ~ "freezing"))

##   [1] "warm"     "warm"     "warm"     "warm"     "warm"     "mild"    
##   [7] "warm"     "warm"     "cold"     "mild"     "mild"     "warm"    
##  [13] "mild"     "warm"     "mild"     "cool"     "mild"     "cold"    
##  [19] "cool"     "warm"     "mild"     "mild"     "mild"     "warm"    
##  [25] "mild"     "warm"     "mild"     "mild"     "mild"     "mild"    
##  [31] "warm"     "cool"     "freezing" "mild"     "mild"     "warm"    
##  [37] "mild"     "cool"     "mild"     "mild"     "mild"     "mild"    
##  [43] "warm"     "warm"     "warm"     "mild"     "mild"     "mild"    
##  [49] "mild"     "mild"     "mild"     "hot"      "mild"     "warm"    
##  [55] "hot"      "warm"     "mild"     "hot"      "cool"     "cold"    
##  [61] "warm"     "cold"     "hot"      "warm"     "cool"     "cool"    
##  [67] "warm"     "mild"     "mild"     "mild"     "cold"     "cool"    
##  [73] "mild"     "cool"     "warm"     "cold"     "warm"     "warm"    
##  [79] "cool"     "mild"     "mild"     "warm"     "mild"     "warm"    
##  [85] "warm"     "cool"     "mild"     "mild"     "warm"     "hot"     
##  [91] "mild"     "warm"     "warm"     "mild"     "warm"     "cool"    
##  [97] "mild"     "mild"     "cool"     "warm"

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