How to verify if when a column is NA the other is not?

I have a dataframe with two columns. I need to check if where a column is NA the other is not. Thanks

Edited.

I would like to know, for each row of the dataframe, if there are rows with both columns not NA.

>Solution :

You can use the following code to check which row has no NA values:

df <- data.frame(x = c(1, NA),
                 y = c(2, NA))

which(rowSums(is.na(df))==ncol(df))

Output:

[1] 1

As you can see the first rows has no NA values so both columns have no NA values.