I have a matrix with missing values. Now I would like to find the missing values, which I did with this `apply`

command.

```
missing <- apply(is.na(matrix), 1, which)
```

It prints me each row name and if there is a missing value or not. But I would like to print only the row names where there are missing values and which ones. So I tried:

```
for(i in length(missing) != 0L) {
print(i)
}
```

But this doesn’t seem to work.

### >Solution :

Create a matrix with some missings

```
mt <- matrix(sample(c(1:5, NA), 50, replace = TRUE), nrow = 5)
```

From the question; adjusted object names

```
miss <- apply(is.na(mt), 1, which)
```

Detect which entries of `miss`

have length of zero and store

the result as a logical vector

```
miss_row_lgl <- sapply(miss, \(x) length(x) != 0)
```

Use logical vector to subset `miss`

```
miss[miss_row_lgl]
#> [[1]]
#> [1] 1 7 9
#>
#> [[2]]
#> [1] 7
#>
#> [[3]]
#> [1] 6
#>
#> [[4]]
#> [1] 9
```