R remove groups with only NAs

Question

I have a dataframe similar to the one generated by the following structure:

library(dplyr)

df1 <- expand.grid(region   = c(\"USA\", \"EUR\", \"World\"),
         


        

Answer 1

To keep only combinations of region and variable that have at least 1 non-NA entry in value you can use:

df %>% group_by(region, variable) %>% filter(any(!is.na(value)))

Or equivalently:

df %>% group_by(region, variable) %>% filter(!all(is.na(value)))

And with data.table you could use:

library(data.table)
setDT(df)[, if(any(!is.na(value))) .SD, by = .(region, variable)]

An approach in base R could be:

df_split <- split(df, interaction(df$region, df$scenario, df$variable))
do.call(rbind.data.frame, df_split[sapply(df_split, function(x) any(!is.na(x$value)))])