How to find the frequency of NA values per row in an R data frame?

Since column represent variables, we often find missing values in the columns of a data frame but we may want to find missing values(NA) for cases as well so that we can replace them based on case characteristic instead of the distribution of the variable. In R, we can use rowSums with apply function.

Example

Consider the below data frame −

 Live Demo

set.seed(8)
x1<-sample(c(NA,1,2),20,replace=TRUE)
x2<-sample(c(NA,5,10),20,replace=TRUE)
df1<-data.frame(x1,x2)
df1

Output

  x1 x2
1  2 10
2  1 10
3  2 5
4  2 10
5  1 5
6  2 NA
7  1 5
8 NA 10
9 NA 10
10 1 5
11 2 NA
12 2 5
13 1 NA
14 1 5
15 2 5
16 1 NA
17 NA 5
18 NA 10
19 1 5
20 2 5

Finding the frequency of NA values in rows of the data frame df1 −

Example

df1$NA_frequency<-rowSums(apply(is.na(df1),2,as.numeric))
df1

Output

  x1 x2 NA_frequency
1  2 10    0
2  1 10    0
3  2 5     0
4  2 10    0
5  1 5     0
6  2 NA    1
7  1 5     0
8 NA 10    1
9 NA 10    1
10 1 5     0
11 2 NA    1
12 2 5     0
13 1 NA    1
14 1 5     0
15 2 5     0
16 1 NA    1
17 NA 5    1
18 NA 10   1
19 1 5     0
20 2 5     0

Let’s have a look at another example −

Example

 Live Demo

y1<-sample(c(NA,1),20,replace=TRUE)
y2<-sample(c(NA,400),20,replace=TRUE)
y3<-sample(c(NA,35),20,replace=TRUE)
y4<-sample(c(NA,127),20,replace=TRUE)
df2<-data.frame(y1,y2,y3,y4)
df2

Output

  y1  y2 y3 y4
1  NA NA 35 127
2  1  NA NA NA
3  1 400 35 127
4  1 NA 35 127
5  1 NA 35 127
6 NA 400 NA NA
7  1 400 NA NA
8  1 NA 35 127
9  1 400 NA 127
10 NA 400 35 127
11 NA NA 35 NA
12 NA NA NA NA
13 NA NA 35 NA
14 1 400 35 NA
15 1 NA 35 NA
16 NA 400 35 NA
17 1 NA 35 NA
18 NA 400 35 127
19 NA 400 NA NA
20 1 NA NA 127

Finding the frequency of NA values in rows of the data frame df2 −

Example

df2$NA_frequency<-rowSums(apply(is.na(df2),2,as.numeric))
df2

Output

  y1 y2 y3 y4 NA_frequency
1 NA NA 35 127    2
2  1 NA NA NA     3
3  1 400 35 127   0
4  1 NA 35 127    1
5  1 NA 35 127    1
6 NA 400 NA NA    3
7  1 400 NA NA    2
8  1 NA 35 127    1
9  1 400 NA 127   1
10 NA 400 35 127  1
11 NA NA 35 NA    3
12 NA NA NA NA    4
13 NA NA 35 NA    3
14 1 400 35 NA    1
15 1 NA 35 NA     2
16 NA 400 35 NA   2
17 1  NA 35 NA    2
18 NA 400 35 127  1
19 NA 400 NA NA   3
20 1 NA NA 127    2

Nizamuddin Siddiqui

Updated on: 17-Oct-2020

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