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rdataframemissing-data

How to only show true rows in a vector including NA values in R

The basic setting looks as follows:

example_data <- data.frame(num=1:5, let=letters[1:5])

complicated_criterium <- function(data) { c(T, NA, F, T, F)}

example_data[complicated_criterium(example_data), ]

This shows the following:

   num  let
1  1    a
NA NA   <NA>
4  4    d

I would like to only see rows 1 and 4, the rows where my complicated criterium is true. What is a simple way to achieve that?

It is correct that the complicated criterium spits on NA on row 2 so I don't want to change that behavior. I played around with is.na and na.omit but logically combining NA with T or F just gives NA again and omitting the NA changes the length of the vector so I don't get the correct rows anymore.

Solution

  • You can just wrap it in which()

    example_data[which(complicated_criterium(example_data)),]

    Output:

      num let
1   1   a
4   4   d