# How to create a column of exponent in data frames stored in R list?

To create a column of exponent in data frames stored in R list, we can follow the below steps −

• First of all, create a list of data frames.

• Then, use lapply function to create a column of exponent in data frames stored in the list.

## Example

#### Create the list of data frames

Using data.frame function to create data frames and list function to create the list of those data frames −

df1<-data.frame(x=sample(1:10,25,replace=TRUE))
df2<-data.frame(x=sample(10:20,25,replace=TRUE))
List<-list(df1,df2)
List

## Output

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

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

Create a column of exponent in data frames stored in the list

Using lapply function to create a column of exponent in data frames df1 and df2 stored in the list called List as shown below −

df1<-data.frame(x=sample(1:10,25,replace=TRUE))
df2<-data.frame(x=sample(10:20,25,replace=TRUE))
List<-list(df1,df2)
lapply(List,function(x) {
+ x$Exponent<-exp(x$x)
+ return(x)
+ })

## Output

[[1]]
x Exponent
1  5 148.413159
2 10 22026.465795
3  1 2.718282
4  9 8103.083928
5  4 54.598150
6  7 1096.633158
7  9 8103.083928
8  9 8103.083928
9  1 2.718282
10 8 2980.957987
11 3 20.085537
12 7 1096.633158
13 3 20.085537
14 3 20.085537
15 4 54.598150
16 8 2980.957987
17 2 7.389056
18 10 22026.465795
19 8 2980.957987
20 5 148.413159
21 8 2980.957987
22 3 20.085537
23 1 2.718282
24 4 54.598150
25 3 20.085537
[[2]]
x Exponent
1  13 442413.39
2  15 3269017.37
3  11 59874.14
4  15 3269017.37
5  13 442413.39
6  17 24154952.75
7  14 1202604.28
8  12 162754.79
9  19 178482300.96
10 13 442413.39
11 12 162754.79
12 19 178482300.96
13 12 162754.79
14 18 65659969.14
15 11 59874.14
16 17 24154952.75
17 10 22026.47
18 11 59874.14
19 11 59874.14
20 13 442413.39
21 20 485165195.41
22 12 162754.79
23 17 24154952.75
24 18 65659969.14
25 19 178482300.96