lapply for outliers poisition-CodePudding

I'm using this code to find the outliers in the data frame.

out<-lapply(df[,-1], function(x) boxplot.stats(x)$out)

The first columns are just the names (that's why I'm skipping it). I've found this method to detect the specific position of the outliers.

out_ind <- which(df$col1 %in% c(out))

But in my case, the object "out" is not a single boxplot.stats(x)$out so I cannot run the which formula. How can I write it to find the outliers' position in every single data frame column?

CodePudding user response：

You now have a list, so you need to iterate over it, e.g. using the apply functions:

df  <- mtcars

out<-lapply(df[,-1], function(x) boxplot.stats(x)$out)

out_ind  <- sapply(names(df[,-1]), \(col) which(
    df[[col]] %in% out[[col]]
    )
)
# out_ind
# $cyl
# integer(0)

# $disp
# integer(0)

# $hp
# [1] 31

# $drat
# integer(0)

# $wt
# [1] 16 17

# $qsec
# [1] 9

# $vs
# integer(0)

# $am
# integer(0)

# $gear
# integer(0)

# $carb
# [1] 31