Summarise by group — summarise_by

Summarise data frame variables according to group

Usage

summarise_by_group(df, grp.cols, summarise.cols, fun)

Arguments

df: A data frame
grp.cols: Index the columns to group by. Can index by column name or column number.
summarise.cols: Index the columns that should be summarised. Can index by column name or column number.
fun: The function for summarising (e.g., mean, max etc.)

Value

A data frame

Examples

summarise_by_group(mtcars, "cyl", c(1, 3:ncol(mtcars)), max)
#>   cyl  mpg  disp  hp drat    wt  qsec vs am gear carb
#> 1   4 33.9 146.7 113 4.93 3.190 22.90  1  1    5    2
#> 2   6 21.4 258.0 175 3.92 3.460 20.22  1  1    5    6
#> 3   8 19.2 472.0 335 4.22 5.424 18.00  0  1    5    8
summarise_by_group(mtcars, 2, c(1, 3:ncol(mtcars)), max)
#>   cyl  mpg  disp  hp drat    wt  qsec vs am gear carb
#> 1   4 33.9 146.7 113 4.93 3.190 22.90  1  1    5    2
#> 2   6 21.4 258.0 175 3.92 3.460 20.22  1  1    5    6
#> 3   8 19.2 472.0 335 4.22 5.424 18.00  0  1    5    8
summarise_by_group(mtcars, c(2, 10), c(1, 3, 5:9), max)
#>   cyl gear  mpg  disp drat    wt  qsec vs am
#> 1   4    3 21.5 120.1 3.70 2.465 20.01  1  0
#> 2   4    4 33.9 146.7 4.93 3.190 22.90  1  1
#> 3   4    5 30.4 120.3 4.43 2.140 16.90  1  1
#> 4   6    3 21.4 258.0 3.08 3.460 20.22  1  0
#> 5   6    4 21.0 167.6 3.92 3.440 18.90  1  1
#> 6   6    5 19.7 145.0 3.62 2.770 15.50  0  1
#> 7   8    3 19.2 472.0 3.73 5.424 18.00  0  0
#> 8   8    5 15.8 351.0 4.22 3.570 14.60  0  1
summarise_by_group(mtcars, "cyl", c("mpg", "disp"), max)
#>   cyl  mpg  disp
#> 1   4 33.9 146.7
#> 2   6 21.4 258.0
#> 3   8 19.2 472.0
summarise_by_group(mtcars, "cyl", "mpg", max)
#>   cyl  mpg
#> 1   4 33.9
#> 2   6 21.4
#> 3   8 19.2
summarise_by_group(mtcars, c("cyl",'gear'), c("mpg", "disp"), max)
#>   cyl gear  mpg  disp
#> 1   4    3 21.5 120.1
#> 2   4    4 33.9 146.7
#> 3   4    5 30.4 120.3
#> 4   6    3 21.4 258.0
#> 5   6    4 21.0 167.6
#> 6   6    5 19.7 145.0
#> 7   8    3 19.2 472.0
#> 8   8    5 15.8 351.0
summarise_by_group(mtcars, "cyl", c(1,3), max)
#>   cyl  mpg  disp
#> 1   4 33.9 146.7
#> 2   6 21.4 258.0
#> 3   8 19.2 472.0