How to find the percentage of NAs in a data.frame?

Question

I am trying to find the percentage of NAs in columns as well as inside the whole dataframe:

The first method which I have commented gives me zero and the second method which is not commented gives me a matrix. Not sure what I am missing. Any hint is truly appreciated!

cp.2006<-read.csv(file="cp2006.csv",head=TRUE)

#countNAs <- function(x) { 
#  sum(is.na(x)) 
#} 
#total=0
#for (i in col(cp.2006)) {
#  total=countNAs(i)+total
#}
#print(total)
count<-apply(cp.2006, 1, function(x) sum(is.na(x)))
dims<-dim(cp.2006)
num<-dims[1]*dims[2]
NApercentage<-(count/num) * 100
print(NApercentage)

Answer 1

x = data.frame(x = c(1, 2, NA, 3), y = c(NA, NA, 4, 5))

For the whole dataframe:

sum(is.na(x))/prod(dim(x))

Or

mean(is.na(x))

For columns:

apply(x, 2, function(col)sum(is.na(col))/length(col))

Or

colMeans(is.na(x))