Having NA level for missing values with cut function from R

Question

The cut function in R omits NA. But I want to have a level for missing values. Here is my MWE.

set.seed(12345)
Y <- c(rnorm(n = 50, mean = 500, sd = 1), NA)
Y1 <-  cut(log(Y), 5)
Labs <- levels(Y1)
Labs

[1] "(6.21,6.212]"  "(6.212,6.213]" "(6.213,6.215]" "(6.215,6.217]" "(6.217,6.219]"

Desired Output

[1] "(6.21,6.212]"  "(6.212,6.213]" "(6.213,6.215]" "(6.215,6.217]" "(6.217,6.219]" "NA"

score 9 · Accepted Answer · answered Jul 29 '15 at 15:24

9

You could use addNA

 Labs <- levels(addNA(Y1))
 Labs
#[1] "(6.21,6.212]"  "(6.212,6.213]" "(6.213,6.215]" "(6.215,6.217]"
#[5] "(6.217,6.219]" NA

In the expected output, you had character "NA". But, I think it is better to have real NA as it can be removed/replaced with is.na

 is.na(Labs)
 #[1] FALSE FALSE FALSE FALSE FALSE  TRUE

answered Jul 29 '15 at 15:24

akrun

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Can we also append NA to Y1? – MYaseen208 Jul 29 '15 at 15:48
@MYaseen208 I'm sorry, I didn't get your comment. `addNA(y1)` converts `y1` to a factor with NA as one of its levels. – akrun Jul 29 '15 at 19:31
1

It's okay @akrun. Thanks again for your help. – MYaseen208 Jul 29 '15 at 19:34

score 1 · Answer 2 · edited Jun 15 '18 at 22:55

1

Changing the original MWE's third line to the following stores NA (actually ) in Y1 rather than the external vector Labs. This cleans up analytic tasks like making tables or building models. The NA is also still recognized by is.na().

Y1 <-  factor(cut(log(Y), 5), exclude=NULL)
is.na(levels(Y1))

result:

[1] FALSE FALSE FALSE FALSE FALSE  TRUE

edited Jun 15 '18 at 22:55

wibeasley

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answered May 25 '17 at 19:18

Mike

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Having NA level for missing values with cut function from R

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