I have a data frame like this
col_1 col_2 col_3 col_4
12344 53445 34335 AAA
12545 56565 12123 AAB
NA 54556 32323 ABB
NA NA NA NA
43434 65654 NA ABA
I want to get rows with at least non-NA value, or put another way, rows with all NAs (row 5 in this case) should be removed. Can you give me some advice?