# How to find the number of zeros in each row of a data.table object in R?

To find the number of zeros in each row of a data.table object in R, we can follow the below steps −

• First of all, create a data.table object.

• Then, use rowSums function to find the number of zeros in each row of the data.table object.

## Example

#### Create the data.table object

Let’s create a data.table object as shown below −

library(data.table)
x<-sample(0:3,25,replace=TRUE)
y<-sample(0:3,25,replace=TRUE)
z<-sample(0:3,25,replace=TRUE)
DT<-data.table(x,y,z)
DT

## Output

On executing, the above script generates the below output(this output will vary on your system due to randomization) −

    x y z
1:  1 2 1
2:  1 1 3
3:  0 0 2
4:  3 3 3
5:  2 0 3
6:  1 0 1
7:  2 3 3
8:  2 3 3
9:  3 1 2
10: 0 0 0
11: 2 3 0
12: 3 3 0
13: 0 0 2
14: 2 3 0
15: 0 3 0
16: 3 3 1
17: 2 1 3
18: 1 3 0
19: 3 0 0
20: 1 2 2
21: 2 1 1
22: 0 2 2
23: 0 0 3
24: 3 2 2
25: 1 2 1
x y z

Find the number of zeros in each row

Using rowSums function to find the number of zeros in each row of the data.table object DT −

library(data.table)
x<-sample(0:3,25,replace=TRUE)
y<-sample(0:3,25,replace=TRUE)
z<-sample(0:3,25,replace=TRUE)
DT<-data.table(x,y,z)
DT\$Total_0s<-rowSums(DT==0)
DT

## Output

    x y z Total_0s
1:  1 2 1 0
2:  1 1 3 0
3:  0 0 2 2
4:  3 3 3 0
5:  2 0 3 1
6:  1 0 1 1
7:  2 3 3 0
8:  2 3 3 0
9:  3 1 2 0
10: 0 0 0 3
11: 2 3 0 1
12: 3 3 0 1
13: 0 0 2 2
14: 2 3 0 1
15: 0 3 0 2
16: 3 3 1 0
17: 2 1 3 0
18: 1 3 0 1
19: 3 0 0 2
20: 1 2 2 0
21: 2 1 1 0
22: 0 2 2 1
23: 0 0 3 2
24: 3 2 2 0
25: 1 2 1 0
x y z Total_0s