How to create a column of rounded values in data frames stored in R list?

To create a column of rounded values 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 rounded valuesin 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=rnorm(25)) df2<-data.frame(x=rnorm(25)) 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 -1.60910333 2 -1.03729474 3 -1.40448389 4 -0.24728310 5 1.30467124 6 -1.13207279 7 0.82561709 8 0.16409103 9 -0.78255736 10 0.18421525 11 0.13996475 12 -0.83319702 13 -0.24966421 14 0.97679457 15 1.03381662 16 -0.78863545 17 0.19427251 18 -1.55102854 19 0.51994225 20 -0.75731012 21 -0.08022442 22 -0.62130337 23 -0.82960514 24 1.00996406 25 -1.78565706 [[2]] x 1 -1.61930147 2 -1.34536134 3 0.50974049 4 0.72663429 5 1.36639765 6 -0.32173730 7 -0.70752541 8 -0.48263801 9 1.39796383 10 0.02785204 11 -1.24980801 12 -1.60321222 13 -0.65432900 14 0.35995917 15 0.00399240 16 0.18852787 17 -0.88659596 18 -1.56006812 19 1.44433948 20 -1.40241760 21 -0.59547084 22 -0.03665240 23 0.27673451 24 0.53268773 25 -1.52717234

Create a column of rounded values

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

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

Output

[[1]]        x Rounded 1  -1.60910333 -1.61 2  -1.03729474 -1.04 3  -1.40448389 -1.40 4  -0.24728310 -0.25 5   1.30467124 1.30 6  -1.13207279 -1.13 7   0.82561709 0.83 8   0.16409103 0.16 9  -0.78255736 -0.78 10 0.18421525 0.18 11  0.13996475 0.14 12 -0.83319702 -0.83 13 -0.24966421 -0.25 14 0.97679457 0.98 15 1.03381662 1.03 16 -0.78863545 -0.79 17 0.19427251 0.19 18 -1.55102854 -1.55 19 0.51994225 0.52 20 -0.75731012 -0.76 21 -0.08022442 -0.08 22 -0.62130337 -0.62 23 -0.82960514 -0.83 24 1.00996406 1.01 25 -1.78565706 -1.79 [[2]] x Rounded 1 -1.61930147 -1.62 2 -1.34536134 -1.35 3 0.50974049 0.51 4 0.72663429 0.73 5 1.36639765 1.37 6 -0.32173730 -0.32 7 -0.70752541 -0.71 8 -0.48263801 -0.48 9 1.39796383 1.40 10 0.02785204 0.03 11 -1.24980801 -1.25 12 -1.60321222 -1.60 13 -0.65432900 -0.65 14 0.35995917 0.36 15 0.00399240 0.00 16 0.18852787 0.19 17 -0.88659596 -0.89 18 -1.56006812 -1.56 19 1.44433948 1.44 20 -1.40241760 -1.40 21 -0.59547084 -0.60 22 -0.03665240 -0.04 23 0.27673451 0.28 24 0.53268773 0.53 25 -1.52717234 -1.53