CODEWITHSUNDEEP
rlist
andschar
andschar

Reputation: 3973

extract names of list entries that are NA

I have a list as follows:

mtlist = as.list(mtcars)
mtlist[[2]] = NA
mtlist[[5]] = NA

What's the most concise way to extract the names of the list elements which are NA?

I came up with the solution below. Yet I wonder if there are other better options. Especially all(is.na(x)) seems error prone to me.

names(which(sapply(mtlist, function (x) all(is.na(x)))))

Upvotes: 0

Views: 35

Answers (1)

Sowmya S. Manian
Sowmya S. Manian

Reputation: 3833

You can use is.na() function to check which of the elements of list are NA and extract their names using names() function.

names(mtlist)[is.na(mtlist)]
# [1] "cyl"  "drat"

Upvotes: 2

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