[R] lapply drops colnames

[Jack Tanner]

I want to iterate over a data frame by columns, and as I'm processing 
each column I want to know its column name.

 > a <- as.data.frame(list(1,2,3))
 > colnames(a) <- c("a", "b", "c")
 > colnames(a)
[1] "X1" "X2" "X3"
 > lapply(a, function(x) {print(colnames(x))})
NULL
NULL
NULL
$a
NULL

$b
NULL

$c
NULL

What is lapply doing? Why does it drop the column name of every column 
it's iterating over? How can I get the column name as a string?