CODEWITHSUNDEEP
rdataframena
CodeGuy
CodeGuy

Reputation: 28905

Check if a data frame is itself NA

How can I check if an R data frame is empty? Check out this code. I want to modify it so it never produces an error or warning.

x = sample(1:2,1)
d = NA
if(x == 1) {
    d = data.frame("h"=c(1,2),"q"=c(2,3))
}

#check if data frame is NA
if(is.na(d)) {
    print("d is NA")
}

If x == 1, then it works fine without any warning, otherwise, if x == 2 the following warning is given

Warning message:
In if (is.na(d)) { :
  the condition has length > 1 and only the first element will be used

Upvotes: 2

Views: 6247

Answers (2)

ndr
ndr

Reputation: 1437

You can to set d to NULL:

d <- NULL

and then check whether is.null(d)

Upvotes: 2

Hong Ooi
Hong Ooi

Reputation: 57696

Irrespective of your subject line, it looks like you really want to check if d is a data frame or something else.

if(is.data.frame(d)) {
    # do something sensible with a data frame
}
else print("d is not a data frame!")

Upvotes: 6

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