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How to fill missing values after merging the data frames with another value than NA in R?

R ProgrammingServer Side ProgrammingProgramming

To fill missing values after merging the data frames with another value than NA in R, we can follow the below steps −

  • First of all, create two data frames.

  • Then, merge the data frames by a common column between the two.

  • After that, replace the NAs with another value.

Example

Create the first data frame

Let’s create a data frame as shown below −

ID<-1:10
x<-sample(1:100,10)
df1<-data.frame(ID,x)
df1

Output

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

   ID x
1   1 28
2   2 50
3   3 13
4   4 43
5   5 48
6   6 49
7   7 52
8   8 54
9   9 72
10 10 32

Create the second data frame

Let’s create a data frame as shown below −

ID<-1:15
y<-sample(1:10,15,replace=TRUE)
df2<-data.frame(ID,y)
df2

Output

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

    ID y
1   1  2
2   2  9
3   3 10
4   4  8
5   5 10
6   6  7
7   7  9
8   8  4
9   9  2
10 10  9
11 11  3
12 12  5
13 13 10
14 14  7
15 15  1

Merge the data frames

Using merge function to merge df1 and df2 by ID column −

ID<-1:10
x<-sample(1:100,10)
df1<-data.frame(ID,x)
ID<-1:15
y<-sample(1:10,15,replace=TRUE)
df2<-data.frame(ID,y)
merge(df1,df2,all=TRUE,by="ID")
DF<-merge(df1,df2,all=TRUE,by="ID")
DF

Output

    ID x  y
1   1 28  2
2   2 50  9
3   3 13 10
4   4 43  8
5   5 48 10
6   6 49  7
7   7 52  9
8   8 54  4
9   9 72  2
10 10 32  9
11 11 NA  3
12 12 NA  5
13 13 NA 10
14 14 NA  7
15 15 NA  1

Replace NAs with another value

Using is.na function to replace NAs in DF with dot (.) as shown below −

ID<-1:10
x<-sample(1:100,10)
df1<-data.frame(ID,x)
ID<-1:15
y<-sample(1:10,15,replace=TRUE)
df2<-data.frame(ID,y)
merge(df1,df2,all=TRUE,by="ID")
DF<-merge(df1,df2,all=TRUE,by="ID")
DF[is.na(DF)]<-"."
DF

Output

    ID x  y
1   1 28  2
2   2 50  9
3   3 13 10
4   4 43  8
5   5 48 10
6   6 49  7
7   7 52  9
8   8 54  4
9   9 72  2
10 10 32  9
11 11  .  3
12 12  .  5
13 13  . 10
14 14  .  7
15 15  .  1
raja
Nizamuddin Siddiqui
Updated on 16-Nov-2021 07:12:20

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