CODEWITHSUNDEEP
rfunction
user17616635
user17616635

Reputation: 1

R function to define several factor levels as missing

I have several factors with levels "No answer" and "don't know" which I want to define as missing. However, the function I wrote to achieve this is not working and I cannot figure out why. Example:

y <- factor(c("a", "b", "c", "Don´t know", "No answer"))
z <- factor(c("a", "b", "c", "Don´t know", "No answer"))
y

[1] a          b          c          Don´t know No answer 
Levels: a b c Don´t know No answer

Defining levels as missing for a single variable does work

levels(y)[levels(y)=="Don´t know"|levels(y)=="No answer"]<- NA
y
[1] a    b    c    <NA> <NA>
Levels: a b c

However, applying a function does not.

nafac <- function(x)
{
levels(x)[levels(x)=="Don´t know"|levels(x)=="No answer"]<- NA
}
nafac(z)
z
[1] a          b          c          Don´t know No answer 
Levels: a b c Don´t know No answer

What is the problem with the function? Thank you!

Upvotes: 0

Views: 234

Answers (1)

Samet S&#246;kel
Samet S&#246;kel

Reputation: 2670

we can simply add return to return updated vector;

nafac <- function(x){
levels(x)[levels(x)=="Don´t know"|levels(x)=="No answer"]<- NA
return(x)
}

nafac(z)

output;

a b c <NA> <NA>

Upvotes: 1

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