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

To create a column of division 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 division 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=round(rnorm(25),2),y=round(rnorm(25),2))
df2<-data.frame(x=round(rnorm(25),2),y=round(rnorm(25),2))
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    y
1  -2.47  0.67
2  -0.55  1.44
3  -1.45  1.17
4   1.25 -0.58
5   0.72  0.51
6   0.29 -1.23
7   1.71  1.35
8   0.20  0.57
9  -1.30  0.56
10 -0.74 -1.68
11 -2.48 -0.17
12 -0.12  1.01
13  0.10 -0.56
14 -0.39  0.77
15  0.35  0.19
16 -1.41 -0.47
17 -1.00  1.20
18 -0.44  0.85
19  0.26  0.04
20 -0.86  0.09
21  1.07 -0.84
22  0.02  0.31
23 -0.57 -0.80
24  0.84 -0.12
25 -0.38 -1.51
[[2]]
x    y
1   0.34  1.11
2   0.43 -1.32
3   0.63  0.20
4  -2.04  0.15
5  -0.99  1.15
6  -0.36 -0.59
7   0.15  0.69
8  -0.48 -0.62
9   0.77  0.33
10  0.58 -0.33
11  0.43  0.20
12 -1.16  0.27
13  0.47 -0.35
14 -0.39 -0.34
15  0.11  0.55
16 -0.90  0.02
17 -0.06 -1.58
18 -0.44  0.19
19 -0.15 -0.74
20  1.22 -0.81
21  0.77  0.42
22 -0.46  1.60
23  1.29 -0.20
24  0.58  1.07
25  0.29 -0.87

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

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

df1<-data.frame(x=round(rnorm(25),2),y=round(rnorm(25),2))
df2<-data.frame(x=round(rnorm(25),2),y=round(rnorm(25),2))
List<-list(df1,df2)
lapply(List,function(x) {
+ x$Division<-x$x/x\$y
+ return(x)
+ })

## Output

[[1]]
x    y      Division
1  -2.47  0.67 -3.68656716
2  -0.55  1.44 -0.38194444
3  -1.45  1.17 -1.23931624
4   1.25 -0.58 -2.15517241
5   0.72  0.51  1.41176471
6   0.29 -1.23 -0.23577236
7   1.71  1.35  1.26666667
8   0.20  0.57  0.35087719
9  -1.30  0.56 -2.32142857
10 -0.74 -1.68  0.44047619
11 -2.48 -0.17  14.58823529
12 -0.12  1.01 -0.11881188
13  0.10 -0.56 -0.17857143
14 -0.39  0.77 -0.50649351
15  0.35  0.19  1.84210526
16 -1.41 -0.47  3.00000000
17 -1.00  1.20 -0.83333333
18 -0.44  0.85 -0.51764706
19  0.26  0.04  6.50000000
20 -0.86  0.09 -9.55555556
21  1.07 -0.84 -1.27380952
22  0.02  0.31  0.06451613
23 -0.57 -0.80  0.71250000
24  0.84 -0.12 -7.00000000
25 -0.38 -1.51  0.25165563
[[2]]
x     y     Division
1   0.34  1.11  0.30630631
2   0.43 -1.32 -0.32575758
3   0.63  0.20  3.15000000
4  -2.04  0.15 -13.60000000
5  -0.99  1.15 -0.86086957
6  -0.36 -0.59  0.61016949
7   0.15  0.69  0.21739130
8  -0.48 -0.62  0.77419355
9   0.77  0.33  2.33333333
10  0.58 -0.33 -1.75757576
11  0.43  0.20  2.15000000
12 -1.16  0.27 -4.29629630
13  0.47 -0.35 -1.34285714
14 -0.39 -0.34  1.14705882
15  0.11  0.55  0.20000000
16 -0.90  0.02 -45.00000000
17 -0.06 -1.58  0.03797468
18 -0.44  0.19 -2.31578947
19 -0.15 -0.74  0.20270270
20  1.22 -0.81 -1.50617284
21  0.77  0.42  1.83333333
22 -0.46  1.60 -0.28750000
23  1.29 -0.20 -6.45000000
24  0.58  1.07  0.54205607
25  0.29 -0.87 -0.33333333