Question

As an example, I want a function that will iterate over the columns in a dataframe and print out each column’s data type (e.g., “numeric”, “integer”, “character”, etc)

Without a variable I know I can do class(df$MyColumn) and get the data type. How can I change it so “MyColumn” is a variable?

What I’m trying is

f <- function(df) {

 for(column in names(df)) {
   columnClass = class(df[column])
   print(columnClass)
 }

}

But this just prints out [1] "data.frame" for each column.

Answer 1

Use a comma before column:

for(column in names(df)) {
   columnClass = class(df[,column])
   print(columnClass)
 }