best way to check if an object is null or empty string in r

Question

I want to check if a variable is '' or 'NULL'. I did below:

x =NULL #or ''

if(is.null(x) || x=='') {
    print('nothing')
} else {
    print(x)
}

My question is what is the best way to check this condition? I feel like there is some better way to do this...

G. Grothendieck · Accepted Answer · 2020-04-29 15:56:55Z

4

Rather than check if it is NULL or an empty character string it might make more sense to check if it has a non-zero length and is a string which is not empty. Then the first leg of the if will handle the primary case and the else leg will handle the less common case which seems easier to follow than the other way around.

if (length(x) && nzchar(x)) x else NA

answered Apr 29, 2020 at 15:56

G. Grothendieck

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4 Comments

Ian Campbell Over a year ago

One drawback is that nzchar(NA) && length(NA) evaluates to TRUE. I know this isn't want the OP wanted.

G. Grothendieck Over a year ago

But that is a different condition, not the one asked for in the question.

user2554330 Over a year ago

Using any(nzchar(x)) might be safer; in some circumstances R complains when you give it a vector of logicals to test.

G. Grothendieck Over a year ago

It depends on what is wanted. If a scalar is expected and a vector is given it would be better to raise an error.

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