vapply() - specify your output!

Intermediate R for Finance

Dan Becker

Manager of Data Science Curriculum at Flatiron School

vapply()

args(vapply)

function (X, FUN, FUN.VALUE, ..., USE.NAMES = TRUE) 
NULL

vapply(stock_list, FUN = class, FUN.VALUE = character(1))

 stock_name      ticker       price   good_deal 
"character" "character"   "numeric"   "logical"

vapply(stock_return, 
       FUN = function(x) {c(mean = mean(x), sd = sd(x))},
       FUN.VALUE = numeric(2))

           apple         ibm        micr
mean 0.002838389 0.001926806 0.002472939
sd   0.007157457 0.008130703 0.009943938

Intermediate R for Finance