adding a column across a list of tibbles - r

Question

I am reading using readxl to bring data into R as a list of tibbles.
library("readxl")
library("reshape2")
xlsx_example<-readxl_example("datasets.xlsx")
AllSheets<-lapply(excel_sheets(xlsx_example), read_excel, path=xlsx_example)
AllSheets
This then brings up 4 tibbles, [[1]] through [[4]]].
I would like to add a new column to all four, with a unique label in each. if it were a single data frame I would use
AllSheets%Newcolumn<-"number1"
But this does not work when you have a list of tibbles. Is there a way to add NewColumn to all the sheets, with "number1", "number2", etc in each sheet?

Answer 1

You can use Map for this:
newdf <- Map(function(x, y) {
x$Newcolumn <- y
x
},
AllSheets,
c('Number1', 'Number2', 'Number3', 'Number4'))
And the output
List of 4
$ :Classes ‘tbl_df’, ‘tbl’ and 'data.frame': 150 obs. of 6 variables:
..$ Sepal.Length: num [1:150] 5.1 4.9 4.7 4.6 5 5.4 4.6 5 4.4 4.9 ...
..$ Sepal.Width : num [1:150] 3.5 3 3.2 3.1 3.6 3.9 3.4 3.4 2.9 3.1 ...
..$ Petal.Length: num [1:150] 1.4 1.4 1.3 1.5 1.4 1.7 1.4 1.5 1.4 1.5 ...
..$ Petal.Width : num [1:150] 0.2 0.2 0.2 0.2 0.2 0.4 0.3 0.2 0.2 0.1 ...
..$ Species : chr [1:150] "setosa" "setosa" "setosa" "setosa" ...
..$ Newcolumn : chr [1:150] "Number1" "Number1" "Number1" "Number1" ...
$ :Classes ‘tbl_df’, ‘tbl’ and 'data.frame': 32 obs. of 12 variables:
..$ mpg : num [1:32] 21 21 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 ...
..$ cyl : num [1:32] 6 6 4 6 8 6 8 4 4 6 ...
..$ disp : num [1:32] 160 160 108 258 360 ...
..$ hp : num [1:32] 110 110 93 110 175 105 245 62 95 123 ...
..$ drat : num [1:32] 3.9 3.9 3.85 3.08 3.15 2.76 3.21 3.69 3.92 3.92 ...
..$ wt : num [1:32] 2.62 2.88 2.32 3.21 3.44 ...
..$ qsec : num [1:32] 16.5 17 18.6 19.4 17 ...
..$ vs : num [1:32] 0 0 1 1 0 1 0 1 1 1 ...
..$ am : num [1:32] 1 1 1 0 0 0 0 0 0 0 ...
..$ gear : num [1:32] 4 4 4 3 3 3 3 4 4 4 ...
..$ carb : num [1:32] 4 4 1 1 2 1 4 2 2 4 ...
..$ Newcolumn: chr [1:32] "Number2" "Number2" "Number2" "Number2" ...
$ :Classes ‘tbl_df’, ‘tbl’ and 'data.frame': 71 obs. of 3 variables:
..$ weight : num [1:71] 179 160 136 227 217 168 108 124 143 140 ...
..$ feed : chr [1:71] "horsebean" "horsebean" "horsebean" "horsebean" ...
..$ Newcolumn: chr [1:71] "Number3" "Number3" "Number3" "Number3" ...
$ :Classes ‘tbl_df’, ‘tbl’ and 'data.frame': 1000 obs. of 6 variables:
..$ lat : num [1:1000] -20.4 -20.6 -26 -18 -20.4 ...
..$ long : num [1:1000] 182 181 184 182 182 ...
..$ depth : num [1:1000] 562 650 42 626 649 195 82 194 211 622 ...
..$ mag : num [1:1000] 4.8 4.2 5.4 4.1 4 4 4.8 4.4 4.7 4.3 ...
..$ stations : num [1:1000] 41 15 43 19 11 12 43 15 35 19 ...
..$ Newcolumn: chr [1:1000] "Number4" "Number4" "Number4" "Number4" ...