Delete rows with na in certain columns, only if dummy = 0

November 12, 2021

I want the following statement:

If df$dummy=0 –> delete all rows with na values in column 2:5.

I try

df[df$dummy==0] <- na.omit(df[2:5],)

But it does not function properly.

anyone that can help me?

>Solution :

It’s always better to include a little reproducible example, otherwise the folks here who answer your question will need to do it for you.

Suppose your data frame looks like this:

df <- data.frame(dummy = c(0,  1,  1, 0, 0, 0,  1, 1, 0, 0),
                 col2  = c(1,  NA, 3, 4, 5, NA, 7, 8, 9, 10),
                 col3  = c(1,  2,  3, 4, 5, 6,  7, 8, 9, NA),
                 col4  = c(NA, 2,  3, 4, 5, 6,  7, 8, 9, 10),
                 col5  = c(1,  2,  3, 4, 5, 6,  7, 8, 9, 10))
df
#>    dummy col2 col3 col4 col5
#> 1      0    1    1   NA    1
#> 2      1   NA    2    2    2
#> 3      1    3    3    3    3
#> 4      0    4    4    4    4
#> 5      0    5    5    5    5
#> 6      0   NA    6    6    6
#> 7      1    7    7    7    7
#> 8      1    8    8    8    8
#> 9      0    9    9    9    9
#> 10     0   10   NA   10   10

Then you can filter out the columns where dummy == 0 AND where any row in columns 2:5 have NA by doing:

df[-which(df$dummy == 0 & apply(df[2:5], 1, anyNA)), ]
#>   dummy col2 col3 col4 col5
#> 2     1   NA    2    2    2
#> 3     1    3    3    3    3
#> 4     0    4    4    4    4
#> 5     0    5    5    5    5
#> 7     1    7    7    7    7
#> 8     1    8    8    8    8
#> 9     0    9    9    9    9

You will see that the only NA that remains occurs in a row where dummy == 1, as expected.

^{Created on 2021-11-12 by the reprex package (v2.0.0)}