Remove rows which have all NAs in certain columns

Question

Suppose you have a dataframe with 9 columns. You want to remove cases which have all NAs in columns 5:9. It\'s not at all relevant if there are NAs in columns 1:4.

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Answer 1

You can use all with apply to find rows where all values are NA:

x[!apply(is.na(x[,5:9]), 1, all),]

or negate is.na and test for any:

x[apply(!is.na(x[,5:9]), 1, any),]

or using rowSums like @RHertel wher you dont need to calculate the number of selected rows:

x[rowSums(!is.na(x[,5:9])) > 0,]