Build list of data.frames

Source: R/build_datalist.R

Construct a list of data.frames based upon an input data.frame and a list of one or more at values

build_datalist(data, at = NULL, as.data.frame = FALSE, ...)

Arguments

data

A data.frame containing the original data.
at

A list of one or more named vectors of values, which will be used to specify values of variables in data. All possible combinations are generated. Alternatively, this can be a data frame of combination levels if only a subset of combinations are desired. See examples.
as.data.frame

A logical indicating whether to return a single stacked data frame rather than a list of data frames
…

Ignored.

Value

A list of data.frames, unless as.data.frame = TRUE in which case a single, stacked data frame is returned.

See also

find_data, mean_or_mode, seq_range

Examples

# basic examples
require("datasets")
build_datalist(head(mtcars), at = list(cyl = c(4, 6)))
#> $`4`
#>                    mpg cyl disp  hp drat    wt  qsec vs am gear carb
#> Mazda RX4         21.0   4  160 110 3.90 2.620 16.46  0  1    4    4
#> Mazda RX4 Wag     21.0   4  160 110 3.90 2.875 17.02  0  1    4    4
#> Datsun 710        22.8   4  108  93 3.85 2.320 18.61  1  1    4    1
#> Hornet 4 Drive    21.4   4  258 110 3.08 3.215 19.44  1  0    3    1
#> Hornet Sportabout 18.7   4  360 175 3.15 3.440 17.02  0  0    3    2
#> Valiant           18.1   4  225 105 2.76 3.460 20.22  1  0    3    1
#> 
#> $`6`
#>                    mpg cyl disp  hp drat    wt  qsec vs am gear carb
#> Mazda RX4         21.0   6  160 110 3.90 2.620 16.46  0  1    4    4
#> Mazda RX4 Wag     21.0   6  160 110 3.90 2.875 17.02  0  1    4    4
#> Datsun 710        22.8   6  108  93 3.85 2.320 18.61  1  1    4    1
#> Hornet 4 Drive    21.4   6  258 110 3.08 3.215 19.44  1  0    3    1
#> Hornet Sportabout 18.7   6  360 175 3.15 3.440 17.02  0  0    3    2
#> Valiant           18.1   6  225 105 2.76 3.460 20.22  1  0    3    1
#> 
#> attr(,"at_specification")
#>   index cyl
#> 1     1   4
#> 2     2   6

str(build_datalist(head(mtcars), at = list(cyl = c(4,6), wt = c(2.75,3,3.25))), 1)
#> List of 6
#>  $ 4.2.75:'data.frame':	6 obs. of  11 variables:
#>   ..- attr(*, "at")=List of 2
#>  $ 6.2.75:'data.frame':	6 obs. of  11 variables:
#>   ..- attr(*, "at")=List of 2
#>  $ 4.3   :'data.frame':	6 obs. of  11 variables:
#>   ..- attr(*, "at")=List of 2
#>  $ 6.3   :'data.frame':	6 obs. of  11 variables:
#>   ..- attr(*, "at")=List of 2
#>  $ 4.3.25:'data.frame':	6 obs. of  11 variables:
#>   ..- attr(*, "at")=List of 2
#>  $ 6.3.25:'data.frame':	6 obs. of  11 variables:
#>   ..- attr(*, "at")=List of 2
#>  - attr(*, "at_specification")='data.frame':	6 obs. of  3 variables:

str(build_datalist(head(mtcars), at = data.frame(cyl = c(4,4), wt = c(2.75,3))))
#> List of 2
#>  $ 4.2.75:'data.frame':	6 obs. of  11 variables:
#>   ..$ mpg : num [1:6] 21 21 22.8 21.4 18.7 18.1
#>   ..$ cyl : num [1:6] 4 4 4 4 4 4
#>   ..$ disp: num [1:6] 160 160 108 258 360 225
#>   ..$ hp  : num [1:6] 110 110 93 110 175 105
#>   ..$ drat: num [1:6] 3.9 3.9 3.85 3.08 3.15 2.76
#>   ..$ wt  : num [1:6] 2.75 2.75 2.75 2.75 2.75 2.75
#>   ..$ qsec: num [1:6] 16.5 17 18.6 19.4 17 ...
#>   ..$ vs  : num [1:6] 0 0 1 1 0 1
#>   ..$ am  : num [1:6] 1 1 1 0 0 0
#>   ..$ gear: num [1:6] 4 4 4 3 3 3
#>   ..$ carb: num [1:6] 4 4 1 1 2 1
#>   ..- attr(*, "at")=List of 2
#>   .. ..$ cyl: num 4
#>   .. ..$ wt : num 2.75
#>  $ 4.3   :'data.frame':	6 obs. of  11 variables:
#>   ..$ mpg : num [1:6] 21 21 22.8 21.4 18.7 18.1
#>   ..$ cyl : num [1:6] 4 4 4 4 4 4
#>   ..$ disp: num [1:6] 160 160 108 258 360 225
#>   ..$ hp  : num [1:6] 110 110 93 110 175 105
#>   ..$ drat: num [1:6] 3.9 3.9 3.85 3.08 3.15 2.76
#>   ..$ wt  : num [1:6] 3 3 3 3 3 3
#>   ..$ qsec: num [1:6] 16.5 17 18.6 19.4 17 ...
#>   ..$ vs  : num [1:6] 0 0 1 1 0 1
#>   ..$ am  : num [1:6] 1 1 1 0 0 0
#>   ..$ gear: num [1:6] 4 4 4 3 3 3
#>   ..$ carb: num [1:6] 4 4 1 1 2 1
#>   ..- attr(*, "at")=List of 2
#>   .. ..$ cyl: num 4
#>   .. ..$ wt : num 3
#>  - attr(*, "at_specification")='data.frame':	2 obs. of  3 variables:
#>   ..$ index: int [1:2] 1 2
#>   ..$ cyl  : num [1:2] 4 4
#>   ..$ wt   : num [1:2] 2.75 3