1 Introduction

This is a set of reproducible examples for the R¹ Hmisc package², put together in an rmarkdown html document using RStudio and knitr. When viewing the resulting html file you can see all the code, and there exist options to download the entire rmarkdown script, which is especially helpful for seeing how knitr chunks are specified. Graphics that have a plotly method for them are rendered using plotly instead of using defaults such as base graphics, lattice, or ggplot2. That way the plots are somewhat interactive, e.g., allow for drill-down for more information without the viewer needing to install R.

Much of the tabular output produced here was created using html methods, which are especially easy to implement with rmarkdown and make for output that can be directly opened using word processors. Jump to Computing Environment for a list of packages used here, and their version numbers.

Rmarkdown themes such as bookdown and rmdformats::readthedown (the latter is used here) allow one to number figures and the symbolically reference them. The knitrSet capfile='captions.md' argument below capitalizes on this to make it easy for the user to insert a table of figures anywhere in the report. Here we place it at the end. A caption listed in the table of figures is the short caption (scap= or fig.scap in the chunk header) if there is one, otherwise the long caption is used. If neither caption is used, that figure will not appear in the table of figures.

The full script for this report may be found here.

2 Setup

require(Hmisc)

knitrSet(lang='markdown', h=4.5, fig.path='png/', fig.align='left',
         capfile='captions.md')  # + sometimes ,cache=TRUE
# knitrSet redirects all messages to messages.txt
options(grType='plotly') # for certain graphics functions
mu <- markupSpecs$html   # markupSpecs is in Hmisc
cap  <- mu$cap           # function to output html caption
lcap <- mu$lcap          # for continuation for long caption
# These last 2 functions are used by the putHfig function in Hmisc
cat('', file='captions.md')   # initialize table of short captions

The following (r mu$styles()) defines HTML styles and javascript functions, such as ffig, smg and the function for expanding and collapsing text as done by the expcoll function.

Here is an example using expcoll. Click on the down arrow to expand; it turns to an up arrow which can be clicked to contract.

▼Example table

x1	x2
0.42315926	a
0.97582612	b
0.16015619	c
0.73837588	d
0.28794946	e
0.75077611	f
0.29967719	g
0.32767614	h
0.06572181	i
0.09975020	j

3 Fetching Data, Modifying Variables, and Printing Data Dictionary

The getHdata function is used to fetch a dataset from the Vanderbilt DataSets web site hbiostat.org/data. The upData function is used to

create a new variable from an old one
add labels to 2 variables
add units to the new variable
remove the old variable
automatically move units of measurements from parenthetical expressions in labels to separate units attributed used by Hmisc and rms functions for table making and graphics

contents is used to print a data dictionary, run through an html method for nicer output. Information about the data source may be found here. Click on the number of levels in the contents table to jump to the value labels for the variable.

getHdata(pbc)

# Have upData move units from labels to separate attribute
pbc <- upData(pbc,
              fu.yrs = fu.days / 365.25,
              labels = c(fu.yrs = 'Follow-up Time',
                         status = 'Death or Liver Transplantation'),
              units = c(fu.yrs = 'year'),
              drop  = 'fu.days',
              moveUnits=TRUE, html=TRUE)

Input object size:   80952 bytes;    19 variables    418 observations
 Label for bili changed from Serum Bilirubin (mg/dl) to Serum Bilirubin 
    units set to mg/dl 
 Label for albumin changed from Albumin (gm/dl) to Albumin 
    units set to gm/dl 
 Label for protime changed from Prothrombin Time (sec.) to Prothrombin Time 
    units set to sec. 
 Label for alk.phos changed from Alkaline Phosphatase (U/liter) to Alkaline Phosphatase 
    units set to U/liter 
 Label for sgot changed from SGOT (U/ml) to SGOT 
    units set to U/ml 
 Label for chol changed from Cholesterol (mg/dl) to Cholesterol 
    units set to mg/dl 
 Label for trig changed from Triglycerides (mg/dl) to Triglycerides 
    units set to mg/dl 
 Label for platelet changed from Platelets (per cm^3/1000) to Platelets 
    units set to per cm^3/1000 
 Label for copper changed from Urine Copper (ug/day) to Urine Copper 
    units set to ug/day 
 Added variable     fu.yrs
 Dropped variable   fu.days
 New object size:   84744 bytes;    19 variables    418 observations

# The following can also be done by running this command
# to put the results in a new browser tab:
# getHdata(pbc, 'contents')
html(contents(pbc), maxlevels=10, levelType='table')

Data frame:pbc

418 observations and 19 variables, maximum # NAs:136

Name	Labels	Units	Levels	Storage	NAs
bili	Serum Bilirubin	mg/dl		double	0
albumin	Albumin	gm/dl		double	0
stage	Histologic Stage, Ludwig Criteria			integer	6
protime	Prothrombin Time	sec.		double	2
sex			2	integer	0
age	Age			double	0
spiders			2	integer	106
hepatom			2	integer	106
ascites			2	integer	106
alk.phos	Alkaline Phosphatase	U/liter		double	106
sgot	SGOT	U/ml		double	106
chol	Cholesterol	mg/dl		integer	134
trig	Triglycerides	mg/dl		integer	136
platelet	Platelets	per cm^3/1000		integer	110
drug			3	integer	0
status	Death or Liver Transplantation			integer	0
edema			3	integer	0
copper	Urine Copper	ug/day		integer	108
fu.yrs	Follow-up Time	year		double	0

Variable	Levels
sex	male
	female
spiders, hepatom	absent
ascites	present
drug	D-penicillamine
	placebo
	not randomized
edema	no edema
	edema, no diuretic therapy
	edema despite diuretic therapy

4 Descriptive Statistics Without Stratification

The html method is used for the describe function, and the output is put in a scrollable box. Other than for the overall title and variable names and labels, the output size used here is 80 (0.8 × the usual font size¹). But the graphical display of the descriptives statistics that follows this is probably better.

# did have results='asis' above
d <- describe(pbc)
html(d, size=80, scroll=TRUE)

pbc

19 Variables 418 Observations

bili: Serum Bilirubin mg/dl

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
418	0	98	0.998	3.221	3.742	0.50	0.60	0.80	1.40	3.40	8.03	14.00

lowest : 0.3 0.4 0.5 0.6 0.7 , highest: 21.6 22.5 24.5 25.5 28.0

albumin: Albumin gm/dl

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
418	0	154	1	3.497	0.473	2.750	2.967	3.243	3.530	3.770	4.010	4.141

lowest : 1.96 2.10 2.23 2.27 2.31 , highest: 4.30 4.38 4.40 4.52 4.64

stage: Histologic Stage, Ludwig Criteria

n	missing	distinct	Info	Mean	Gmd
412	6	4	0.893	3.024	0.9519

 Value          1     2     3     4
 Frequency     21    92   155   144
 Proportion 0.051 0.223 0.376 0.350

protime: Prothrombin Time sec.

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
416	2	48	0.998	10.73	1.029	9.60	9.80	10.00	10.60	11.10	12.00	12.45

lowest : 9.0 9.1 9.2 9.3 9.4 , highest: 13.8 14.1 15.2 17.1 18.0

sex

n	missing	distinct
418	0	2

 Value        male female
 Frequency      44    374
 Proportion  0.105  0.895

age: Age

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
418	0	345	1	50.74	11.96	33.84	36.37	42.83	51.00	58.24	64.30	67.92

lowest : 26.27789 28.88433 29.55510 30.27515 30.57358 , highest: 74.52430 75.00000 75.01164 76.70910 78.43943

spiders

n	missing	distinct
312	106	2

 Value       absent present
 Frequency      222      90
 Proportion   0.712   0.288

hepatom

n	missing	distinct
312	106	2

 Value       absent present
 Frequency      152     160
 Proportion   0.487   0.513

ascites

n	missing	distinct
312	106	2

 Value       absent present
 Frequency      288      24
 Proportion   0.923   0.077

alk.phos: Alkaline Phosphatase U/liter

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
312	106	295	1	1983	1760	599.6	663.0	871.5	1259.0	1980.0	3826.4	6669.9

lowest : 289.0 310.0 369.0 377.0 414.0 , highest: 11046.6 11320.2 11552.0 12258.8 13862.4

sgot: SGOT U/ml

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
312	106	179	1	122.6	60.45	54.25	60.45	80.60	114.70	151.90	196.47	219.25

lowest : 26.35 28.38 41.85 43.40 45.00 , highest: 288.00 299.15 328.60 338.00 457.25

chol: Cholesterol mg/dl

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
284	134	201	1	369.5	194.5	188.4	213.6	249.5	309.5	400.0	560.8	674.0

lowest : 120 127 132 149 151 , highest: 1336 1480 1600 1712 1775

trig: Triglycerides mg/dl

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
282	136	146	1	124.7	64.07	56.00	63.10	84.25	108.00	151.00	195.00	230.95

lowest : 33 44 46 49 50 , highest: 319 322 382 432 598

platelet: Platelets per cm³/1000

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
308	110	210	1	261.9	107.8	117.7	139.7	199.8	257.0	322.5	386.5	430.6

lowest : 62 70 71 79 80 , highest: 493 514 518 539 563

drug

n	missing	distinct
418	0	3

 Value      D-penicillamine         placebo  not randomized
 Frequency              154             158             106
 Proportion           0.368           0.378           0.254

status: Death or Liver Transplantation

n	missing	distinct	Info	Sum	Mean	Gmd
418	0	2	0.71	161	0.3852	0.4748

edema

n	missing	distinct
418	0	3

 Value                            no edema     edema, no diuretic therapy
 Frequency                             354                             44
 Proportion                          0.847                          0.105
                                          
 Value      edema despite diuretic therapy
 Frequency                              20
 Proportion                          0.048

copper: Urine Copper ug/day

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
310	108	158	1	97.65	83.16	17.45	24.00	41.25	73.00	123.00	208.10	249.20

lowest : 4 9 10 11 12 , highest: 412 444 464 558 588

fu.yrs: Follow-up Time year

n	missing	distinct	Info	Mean	Gmd	.05	.10	.25	.50	.75	.90	.95
418	0	399	1	5.251	3.429	0.671	1.661	2.992	4.736	7.155	9.649	11.063

lowest :	0.1122519	0.1177276	0.1396304	0.1943874	0.2108145
highest:	12.3203285	12.3449692	12.3832991	12.4736482	13.1279945

# prList is in Hmisc; useful for plotting or printing a list of objects
# Can just use plot(d) if don't care about the mess
# If using html output these 2 images would not be rendered no matter what
p <- plot(d)
# The option htmlfig=2 causes markupSpecs$html$cap() to be used to
# HTML-typeset as a figure caption and to put the sub-sub section
# marker ### in front of the caption.  htmlfig is the only reason
# results='asis' was needed in the chunk header
# We define a long caption for one of the plots, which does not appear
# in the table of contents
# prList works for html notebooks but not html documents
# prList(p, lcap=c('', 'These are spike histograms'), htmlfig=2)

You can also re-form multiple plotly graphs into a single HTML object. If you want to have total control over long and short figure captions, use the Hmisc putHfig function to render the result, with a caption and a short caption for the table of contents. That would have fixed a problem with the chunk below: when plotly graphics are not rendered in the usual way, the figure is not numbered and no caption appears.

htmltools::tagList(p)    # lapply(p, plotly::as.widget)

Hmisc Examples