R Tips

Basic R

1. Use column names as the iterable with sapply.

   iris_data <- iris[,-5]
   par(mfrow = c(2,2))
   temp <- sapply(colnames(iris_data), function(x) plot(iris_data[,x], main = x))
   

   

2. Use setNames(object = nm, nm) to give values names.
   • Example: We want to add IQR alongside with summary

     > c(summary(iris$Sepal.Length), setNames(IQR(iris$Sepal.Length), 'IQR'))
     

      Min.  1st Qu.   Median     Mean  3rd Qu.     Max.      IQR 
     4.300000 5.100000 5.800000 5.843333 6.400000 7.900000 1.300000
     

3. Use such form (function(x) do_stuff_with(x)) (a) to apply a anonymous function to a single variable.
   • Example: We want to add IQR, SD and Var along side with summary

     > (function(x) print(c(summary(x), setNames(IQR(x), 'IQR'), setNames(sd(x), 'SD'), setNames(var(x), 'Var')))) (iris$Sepal.Length)
     

       Min.   1st Qu.    Median      Mean   3rd Qu.      Max.       IQR        SD       Var 
     4.3000000 5.1000000 5.8000000 5.8433333 6.4000000 7.9000000 1.3000000 0.8280661 0.6856935