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Motivation

Occasionally it is useful to generate a table of summary statistics for rows of a dataset, where such rows represent sampling units and and columns may be categorical or continuous. The excellent R package table1 does exactly this, and was the inspiration for tablet. table1 however is optimized for html; tablet tries to provide a format-neutral implementation and relies on kableExtra to handle the rendering. Support for pdf (latex) is of particular interest, and is illustrated in the companion vignette. Here we convert that presentation to html for completeness. If you only need html output, you may prefer the interface, flexibility, and styling options of table1.

Software

To support our examples, we load some other packages and in particular locate the melanoma dataset from boot.

library(tidyr)
library(dplyr)
library(magrittr)
library(kableExtra)
library(boot)
library(yamlet)
library(tablet)
x <- melanoma
x %<>% select(-time, -year)

Simple Case

For starters, we’ll just coerce two variables to factor to show that they are categorical, and then pass the whole thing to tablet(). Then we forward to as_kable() for rendering (calls kableExtra::kbl and adds some magic).

x %>%
  mutate(
    sex = factor(sex), 
    ulcer = factor(ulcer)
  ) %>%
  tablet %>%
  as_kable
All
(N = 205)
status
Mean (SD) 1.79 (0.551)
Median (range) 2 (1, 3)
sex
0 126 (61.5%)
1 79 (38.5%)
age
Mean (SD) 52.5 (16.7)
Median (range) 54 (4, 95)
thickness
Mean (SD) 2.92 (2.96)
Median (range) 1.94 (0.1, 17.4)
ulcer
0 115 (56.1%)
1 90 (43.9%)

With Metadata

Now we redefine the dataset, supplying metadata almost verbatim from ?melanoma. This is fairly easy using package yamlet. Note that we reverse the authors’ factor order of 1, 0 for ulcer and move status ‘Alive’ to first position.

x <- melanoma

x %<>% decorate('
time:      [ Survival Time Since Operation, day ]
status:
 - End of Study Patient Status
 -
  - Alive: 2
  - Melanoma Death: 1
  - Unrelated Death: 3
sex:       [ Sex, [ Male: 1, Female: 0 ]]
age:       [ Age at Time of Operation, year ]
year:      [ Year of Operation, year ]
thickness: [ Tumor Thickness, mm ]
ulcer:     [ Ulceration, [ Absent: 0, Present: 1 ]]
')
x %<>% select(-time, -year)
x %<>% group_by(status)
x %<>% resolve

Now we pass x to tablet() and as_kable() for a more informative result.

x %>% tablet %>% as_kable
Alive
(N = 134)
Melanoma Death
(N = 57)
Unrelated Death
(N = 14)
All
(N = 205)
Sex
Male 43 (32.1%) 29 (50.9%) 7 (50%) 79 (38.5%)
Female 91 (67.9%) 28 (49.1%) 7 (50%) 126 (61.5%)
Age at Time of Operation (year)
Mean (SD) 50 (15.9) 55.1 (17.9) 65.3 (10.9) 52.5 (16.7)
Median (range) 52 (4, 84) 56 (14, 95) 65 (49, 86) 54 (4, 95)
Tumor Thickness (mm)
Mean (SD) 2.24 (2.33) 4.31 (3.57) 3.72 (3.63) 2.92 (2.96)
Median (range) 1.36 (0.1, 12.9) 3.54 (0.32, 17.4) 2.26 (0.16, 12.6) 1.94 (0.1, 17.4)
Ulceration
Absent 92 (68.7%) 16 (28.1%) 7 (50%) 115 (56.1%)
Present 42 (31.3%) 41 (71.9%) 7 (50%) 90 (43.9%)

Notice that:

If you don’t particularly care for some aspect of the presentation, you can jump in between tablet() and as_kable() to fix things up. For example, if you don’t want the “All” column you can just say

If you only want the the “All” column, you can just remove the group(s):

By the way, you can also pass all = NULL to suppress the ‘All’ column.

Grouped Columns

In tablet(), most columns are the consequences of a grouping variable. Not surprisingly, grouped columns are just a consequence of nested grouping variables. To illustrate, we follow the table1 vignette by adding a grouping variable that groups the two kinds of death.

x %<>% mutate(class = status)                          # copy the current group
x %<>% modify(class, label = 'class')                  # change its label
levels(x$status) <- c('Alive','Melanoma','Unrelated')  # tweak current group
levels(x$class)  <- c(' ',    'Death',   'Death')      # cluster groups
x %<>% group_by(class, status)                         # nest groups
x %>% tablet %>% as_kable                              # render
Death
Alive
(N = 134)
Melanoma
(N = 57)
Unrelated
(N = 14)
All
(N = 205)
Sex
Male 43 (32.1%) 29 (50.9%) 7 (50%) 79 (38.5%)
Female 91 (67.9%) 28 (49.1%) 7 (50%) 126 (61.5%)
Age at Time of Operation (year)
Mean (SD) 50 (15.9) 55.1 (17.9) 65.3 (10.9) 52.5 (16.7)
Median (range) 52 (4, 84) 56 (14, 95) 65 (49, 86) 54 (4, 95)
Tumor Thickness (mm)
Mean (SD) 2.24 (2.33) 4.31 (3.57) 3.72 (3.63) 2.92 (2.96)
Median (range) 1.36 (0.1, 12.9) 3.54 (0.32, 17.4) 2.26 (0.16, 12.6) 1.94 (0.1, 17.4)
Ulceration
Absent 92 (68.7%) 16 (28.1%) 7 (50%) 115 (56.1%)
Present 42 (31.3%) 41 (71.9%) 7 (50%) 90 (43.9%)

Transposed Groups

Categorical observations (in principle) and grouping variables are all factors, and are thus transposable. To illustrate, we drop the column group above and instead nest sex within status …

x %<>% group_by(status, sex)
x %<>% select(-class)
x %>% 
  tablet %>% 
  as_kable
Alive
Melanoma
Unrelated
Male
(N = 43)
Female
(N = 91)
Male
(N = 29)
Female
(N = 28)
Male
(N = 7)
Female
(N = 7)
All
(N = 205)
Age at Time of Operation (year)
Mean (SD) 52.5 (16.9) 48.8 (15.4) 53.9 (19.7) 56.4 (16.2) 62.4 (11.2) 68.1 (10.6) 52.5 (16.7)
Median (range) 55 (12, 84) 49 (4, 77) 52 (19, 95) 58 (14, 89) 64 (49, 76) 66 (54, 86) 54 (4, 95)
Tumor Thickness (mm)
Mean (SD) 2.73 (2.49) 2.02 (2.22) 4.63 (3.47) 3.99 (3.71) 4.83 (4.19) 2.6 (2.84) 2.92 (2.96)
Median (range) 1.62 (0.16, 8.38) 1.29 (0.1, 12.9) 4.04 (0.81, 14.7) 3.14 (0.32, 17.4) 4.84 (0.65, 12.6) 1.45 (0.16, 8.54) 1.94 (0.1, 17.4)
Ulceration
Absent 24 (55.8%) 68 (74.7%) 8 (27.6%) 8 (28.6%) 4 (57.1%) 3 (42.9%) 115 (56.1%)
Present 19 (44.2%) 23 (25.3%) 21 (72.4%) 20 (71.4%) 3 (42.9%) 4 (57.1%) 90 (43.9%)

… or nest ulceration within status …

x %<>% group_by(status, ulcer)
x %>% 
  tablet %>% 
  as_kable
Alive
Melanoma
Unrelated
Absent
(N = 92)
Present
(N = 42)
Absent
(N = 16)
Present
(N = 41)
Absent
(N = 7)
Present
(N = 7)
All
(N = 205)
Sex
Male 24 (26.1%) 19 (45.2%) 8 (50%) 21 (51.2%) 4 (57.1%) 3 (42.9%) 79 (38.5%)
Female 68 (73.9%) 23 (54.8%) 8 (50%) 20 (48.8%) 3 (42.9%) 4 (57.1%) 126 (61.5%)
Age at Time of Operation (year)
Mean (SD) 49.3 (15.4) 51.6 (17.1) 54.9 (19.9) 55.1 (17.4) 58.4 (8.66) 72.1 (8.53) 52.5 (16.7)
Median (range) 50 (4, 83) 54.5 (12, 84) 59 (16, 83) 56 (14, 95) 56 (49, 71) 72 (60, 86) 54 (4, 95)
Tumor Thickness (mm)
Mean (SD) 1.63 (1.93) 3.58 (2.58) 2.7 (3.35) 4.94 (3.5) 2.1 (1.93) 5.34 (4.33) 2.92 (2.96)
Median (range) 1.13 (0.1, 12.9) 3.06 (0.32, 12.2) 1.94 (0.32, 14.7) 4.04 (0.97, 17.4) 1.45 (0.65, 6.12) 4.84 (0.16, 12.6) 1.94 (0.1, 17.4)

… or where it makes sense, use multiple levels of nesting.

x %<>% group_by(status, ulcer, sex)
x %>% 
  tablet %>% 
  as_kable
Alive
Melanoma
Unrelated
Absent
Present
Absent
Present
Absent
Present
Male
(N = 24)
Female
(N = 68)
Male
(N = 19)
Female
(N = 23)
Male
(N = 8)
Female
(N = 8)
Male
(N = 21)
Female
(N = 20)
Male
(N = 4)
Female
(N = 3)
Male
(N = 3)
Female
(N = 4)
All
(N = 205)
Age at Time of Operation (year)
Mean (SD) 50.4 (17) 48.9 (14.9) 55.3 (16.9) 48.7 (17) 55.2 (22.2) 54.6 (18.8) 53.3 (19.2) 57 (15.5) 54.5 (7.14) 63.7 (8.74) 73 (2.65) 71.5 (11.8) 52.5 (16.7)
Median (range) 54 (15, 83) 49 (4, 77) 56 (12, 84) 48 (19, 75) 56 (27, 83) 59 (16, 77) 52 (19, 95) 58 (14, 89) 52.5 (49, 64) 66 (54, 71) 72 (71, 76) 70 (60, 86) 54 (4, 95)
Tumor Thickness (mm)
Mean (SD) 1.47 (1.72) 1.69 (2) 4.32 (2.42) 2.97 (2.59) 3.27 (4.68) 2.14 (1.18) 5.14 (2.86) 4.72 (4.13) 2.42 (2.5) 1.67 (1.14) 8.05 (4.02) 3.3 (3.71) 2.92 (2.96)
Median (range) 0.97 (0.16, 7.09) 1.29 (0.1, 12.9) 3.87 (0.81, 8.38) 1.94 (0.32, 12.2) 1.78 (0.81, 14.7) 2.02 (0.32, 3.56) 4.83 (1.62, 12.9) 3.54 (0.97, 17.4) 1.46 (0.65, 6.12) 1.45 (0.65, 2.9) 6.76 (4.84, 12.6) 2.26 (0.16, 8.54) 1.94 (0.1, 17.4)

Aesthetics

tablet tries to give rather exhaustive control over formatting. Much can be achieved by replacing elements of ‘fun’, ‘fac’, ‘num’, and ‘lab’ (see ?tablet.data.frame). For finer control, you can replace these entirely. In this example, we will …

x %<>% group_by(status)
x %>% 
  tablet(
    fac = NULL,
    lab ~ name,
    `Median (range)` ~ med + ' (' + min + ' - ' + max + ')'
  ) %>% 
  as_kable
Alive Melanoma Unrelated All
Age at Time of Operation (year)
Mean (SD) 50 (15.9) 55.1 (17.9) 65.3 (10.9) 52.5 (16.7)
Median (range) 52 (4 - 84) 56 (14 - 95) 65 (49 - 86) 54 (4 - 95)
Tumor Thickness (mm)
Mean (SD) 2.24 (2.33) 4.31 (3.57) 3.72 (3.63) 2.92 (2.96)
Median (range) 1.36 (0.1 - 12.9) 3.54 (0.32 - 17.4) 2.26 (0.16 - 12.6) 1.94 (0.1 - 17.4)

Note

The default presentation includes “N =” under the header, but also has percent characters in the table. Considerable gymnastics are required to make this work in latex. For html, we simply replace the newline character (supplied by ‘lab’) with a ‘br’ tag internally.

Conclusion

tablet gives a flexible way of summarizing tables of observations. It reacts to numeric columns, factors, and grouping variables. Display order derives from the order of columns and factor levels in the data. Result columns can be grouped arbitrarily deep by supplying extra groups. Column labels and titles are respected. Rendering is largely the responsibility of kableExtra and can be extended. Further customization is possible by manipulating data after calling tablet() but before calling as_kable(). Powerful results are possible with very little code.

These binaries (installable software) and packages are in development.
They may not be fully stable and should be used with caution. We make no claims about them.