Introducing terse - a package for compact output of lists and data.frames

2020-07-01

terse

terse is an alternative to str() that aims to be more succinct for simple objects.

It was built with (nested) list output in mind, but handles data.frames and many other standard data structures in R.

Features

  • Compact output
  • ANSI colour (configurable)
  • Alignment of indexes at start of each row, such that names at the same depth are aligned under each other
  • Alignment of values within data.frames

Limitations

  • Currently supports the standard vector types and lists
  • Lists are always recursed in to (there is currently no option to limit the recursion depth)
  • Weirder data structures might not work how you want - e.g. list-columns in data.frames, R6 objects etc.

If you find a common case that doesn’t produce nice output, please file an issue (or PR!).

Installation

You can install from GitHub with:

# install.packages("devtools")
devtools::install_github("coolbutuseless/terse")

Terse data.frame output

Simple data.frame output

library(terse)
terse(mtcars)

Click here to show/hide - Comparison to str() and glimpse()

str(mtcars)
'data.frame':   32 obs. of  11 variables:
 $ mpg : num  21 21 22.8 21.4 18.7 18.1 14.3 24.4 22.8 19.2 ...
 $ cyl : num  6 6 4 6 8 6 8 4 4 6 ...
 $ disp: num  160 160 108 258 360 ...
 $ hp  : num  110 110 93 110 175 105 245 62 95 123 ...
 $ drat: num  3.9 3.9 3.85 3.08 3.15 2.76 3.21 3.69 3.92 3.92 ...
 $ wt  : num  2.62 2.88 2.32 3.21 3.44 ...
 $ qsec: num  16.5 17 18.6 19.4 17 ...
 $ vs  : num  0 0 1 1 0 1 0 1 1 1 ...
 $ am  : num  1 1 1 0 0 0 0 0 0 0 ...
 $ gear: num  4 4 4 3 3 3 3 4 4 4 ...
 $ carb: num  4 4 1 1 2 1 4 2 2 4 ...
dplyr::glimpse(mtcars)
Rows: 32
Columns: 11
$ mpg  <dbl> 21.0, 21.0, 22.8, 21.4, 18.7, 18.1, 14.3, 24.4, 22.8, 19.2, 17.8…
$ cyl  <dbl> 6, 6, 4, 6, 8, 6, 8, 4, 4, 6, 6, 8, 8, 8, 8, 8, 8, 4, 4, 4, 4, 8…
$ disp <dbl> 160.0, 160.0, 108.0, 258.0, 360.0, 225.0, 360.0, 146.7, 140.8, 1…
$ hp   <dbl> 110, 110, 93, 110, 175, 105, 245, 62, 95, 123, 123, 180, 180, 18…
$ drat <dbl> 3.90, 3.90, 3.85, 3.08, 3.15, 2.76, 3.21, 3.69, 3.92, 3.92, 3.92…
$ wt   <dbl> 2.620, 2.875, 2.320, 3.215, 3.440, 3.460, 3.570, 3.190, 3.150, 3…
$ qsec <dbl> 16.46, 17.02, 18.61, 19.44, 17.02, 20.22, 15.84, 20.00, 22.90, 1…
$ vs   <dbl> 0, 0, 1, 1, 0, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 1, 1, 1, 1, 0…
$ am   <dbl> 1, 1, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1, 1, 1, 0, 0…
$ gear <dbl> 4, 4, 4, 3, 3, 3, 3, 4, 4, 4, 4, 3, 3, 3, 3, 3, 3, 4, 4, 4, 3, 3…
$ carb <dbl> 4, 4, 1, 1, 2, 1, 4, 2, 2, 4, 4, 3, 3, 3, 4, 4, 4, 1, 2, 1, 1, 2…

Terse data.frame output - plain ASCII

Simple data.frame output without ANSI

terse(mtcars, config = list(ansi = FALSE), width = 100)
mtcars$mpg  d32 21   , 21   , 22.8 , 21.4 , 18.7 , 18.1 , 14.3 , 24.4 , 22.8 , 19.2 , 17.8 , 16 ...
mtcars$cyl  d32 6    , 6    , 4    , 6    , 8    , 6    , 8    , 4    , 4    , 6    , 6    , 8  ...
mtcars$disp d32 160  , 160  , 108  , 258  , 360  , 225  , 360  , 146.7, 140.8, 167.6, 167.6, 27 ...
mtcars$hp   d32 110  , 110  , 93   , 110  , 175  , 105  , 245  , 62   , 95   , 123  , 123  , 18 ...
mtcars$drat d32 3.9  , 3.9  , 3.85 , 3.08 , 3.15 , 2.76 , 3.21 , 3.69 , 3.92 , 3.92 , 3.92 , 3. ...
mtcars$wt   d32 2.62 , 2.875, 2.32 , 3.215, 3.44 , 3.46 , 3.57 , 3.19 , 3.15 , 3.44 , 3.44 , 4. ...
mtcars$qsec d32 16.46, 17.02, 18.61, 19.44, 17.02, 20.22, 15.84, 20   , 22.9 , 18.3 , 18.9 , 17 ...
mtcars$vs   d32 0    , 0    , 1    , 1    , 0    , 1    , 0    , 1    , 1    , 1    , 1    , 0  ...
mtcars$am   d32 1    , 1    , 1    , 0    , 0    , 0    , 0    , 0    , 0    , 0    , 0    , 0  ...
mtcars$gear d32 4    , 4    , 4    , 3    , 3    , 3    , 3    , 4    , 4    , 4    , 4    , 3  ...
mtcars$carb d32 4    , 4    , 1    , 1    , 2    , 1    , 4    , 2    , 2    , 4    , 4    , 3  ...

Terse nested list output

ll <- list(
  apple = list(
    bob = list(c = 1:3),
    c = list(
      list(d = head(mtcars))
    ),
    ddd = setNames(1:26, letters)
  )
)
terse(ll, config = list(nth = 4, colour_nth = 'red'))

Click here to show/hide - Comparison to str() 

str(ll)
List of 1
 $ apple:List of 3
  ..$ bob:List of 1
  .. ..$ c: int [1:3] 1 2 3
  ..$ c  :List of 1
  .. ..$ :List of 1
  .. .. ..$ d:'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] 6 6 4 6 8 6
  .. .. .. ..$ 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] 2.62 2.88 2.32 3.21 3.44 ...
  .. .. .. ..$ 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
  ..$ ddd: Named int [1:26] 1 2 3 4 5 6 7 8 9 10 ...
  .. ..- attr(*, "names")= chr [1:26] "a" "b" "c" "d" ...

Notes on output

The output consists of 3 sections:

  • Names and indices (on the left)
  • Compact type + length information
  • Vectors of values (on the right)

The green output consists of a single character for type information, followed by a length (the number of elements in this vector)

Click to show/hide list of all type information

  • a - array
  • m - matrix
  • l - logical
  • f - factor
  • p - POSIXct
  • P - POSIXlt
  • D - Date
  • n - name
  • i - integer
  • d - double
  • r - raw
  • c - character
  • C - complex
  • N - null
  • K - call
  • F - function
  • E - environment
  • e - expression
  • L - list
  • x - unknown

Config

terse() takes a config argument which must be a named list. Possible elements are:

  • ansi - Use ANSI colouring? default: TRUE
  • soft - non-highlight colour. default: grey40
  • gsep - separator for vector output. default: ,
  • colour_nth - colour for every nth vector element. default: blue4
  • colour_all - colour for all other vector elements. default: grey40
  • colour_type - colour for the type/length meta information. default: seagreen
  • nth - interval for colouring vector elements. default: 0 (off)

Acknowledgements