MathJax JavaScript functions.
Standard LaTeX input will be turned into MathML and displayed in any
modern browser.
as.latex(x, label = NULL, inline = ifelse(is.null(label), TRUE, FALSE), count = ifelse(is.null(label), FALSE, TRUE))
hwriteLatex(ltx, page = NULL, table.attributes = NULL, tr.attributes = "", td.attributes = NULL, ...)TRUE for a mathematical
expression to be included inline. Set to FALSE for a
displayed mathematical expression.TRUE for a numbered equation,
FALSE otherwise.latex as produced by
as.latex.newPage or openPage.as.latex returns a list of class latex with components:
NULL a character string.hwriteLatex produces a character vector containing the output
HTML code. If page is specified this text is appended to the
specified file.
MathJax JavaScript program. Mathematical expressions can be inserted inline (within text)
or on a single line as a displayed expression, corresponding to the
use of $...$ and
One problem with writing LaTeX expressions is that all backslashes must be repeated. See the examples.
See the examples for an example of arguments to be supplied to
newPage to ensure mathematical expressions are displayed.
If ltx is a string containing a mathematical expression in
LaTeX notation, or if it is an object of class latex with
inline = TRUE then any values assigned to
table.attributes tr.attributes and td.attributes are
ignored. Otherwise the default value of table.attributes when
this argument is NULL depends on whether the mathematical
expression has an equation number or not, which is determined by
whether count in the latex object is TRUE or
FALSE. If count = FALSE then table.attributes is
assigned the value "border = '0'". If count = FALSE then
table.attributes is assigned the value "border = '0'
width = '90%'". Similarly the default value of td.attributes
depends on whether the mathematical expression has an equation number
or not. If count = FALSE then td.attributes is
ignored. If count = FALSE then table.attributes is
assigned the value c("width = '50'","align = 'center'",
"align = 'right' width = '50'"). The explanation for these
assignments is that if a displayed mathematical expression has no
equation number it is constructed as a table comprised of a single row
with a single entry in that row. If the expression has an equation
number, it is constructed as a table comprised of a single row with
three entries: the first is a non-breaking space, the second is the
mathematical expression itself and the third is the equation number.
Note that these functions are modified versions of as.latex and
HTML.latex from the package R2HTML. The most notable
changes are that HTML.latex does not allow for inclusion of
table and table data attributes in mathematical expressions and the
numbering of equations uses R code rather than JavaScript. The
numbering system for equations adds an entry to the global vector
hwriterEquationList whenever a numbered equation is created. If
a label is specified via the label argument, by for example,
label = "anequationlabel", then an anchor is created as part of
the table data entry containing the equation number, using an HTML
a element. The actual anchor name is eq:anequationlabel,
which copies the label categorizing approach used in LaTeX. If no
label is specified, but the equation is numbered, the name used for
the anchor is eq:equationxx where xx is the equation
number. Then the number of an equation corresponding to a given label
may be retrieved using the function eqRef (intended to be
reminiscent of the LaTeX \ref command).
To see what attributes are valid for tables, table rows and table data, go to http://www.w3schools.com/tags/ and click on the desired tag.
newPage
as.latex("See what is added by as.latex", label = "a label",
inline = FALSE, count = TRUE)
### Run this example to see what is written to the file
## Not run:
# ### An inline expression will be written to standard output as is
# ### Note that the backslashes remain duplicated in this case
# ### I think this is due to a line of code in hwriter::hwriteString
# ### if (is.null(page)) txt
# ### which writes the txt literally rather than using cat
# hwrite("Here is an inline mathematical expression:
# `\int_{-\infty}^{1}f(x)dx`")
# ### The same expression but displayed
# hwriteLatex(as.latex("\int_{-\infty}^{1}f(x)dx",
# inline = FALSE, count = FALSE),
# table.attributes = "border = '1'",
# tr.attributes = "bgcolor = 'white'")
#
#
# ### The same example written to a file
# ### Create a temporary file first
# tmpDir <- tempdir()
# fileName <- file.path(tmpDir, 'hwriteLatex.html')
# ### Copy some necessary files
# cssDir <- file.path(system.file(package = 'hwriterPlus'), 'css')
# file.copy(file.path(cssDir, "BrowserExample.css"), tmpDir)
#
# ### Open file for writing
# p <- newPage(fileName,
# title = "Example of a Document for Display in a Browser",
# link.css = c("BrowserExample.css"))
# hwrite("Here is an inline mathematical expression:
# `\int_{-\infty}^{1}f(x)dx`", p, br)
# ### The same expression but displayed
# hwrite("Here is a displayed version of the same expression enclosed in a
# box", p, br)
# hwriteLatex(as.latex("\int_{-\infty}^{1}f(x)dx",
# inline = FALSE, count = FALSE),
# p,
# table.attributes = "border = '1'",
# tr.attributes = "bgcolor = 'white'")
# ### We can also have equation numbers and labels when writing to a file
# hwrite("Here is a different expression which has an equation number and
# assigned a label", p, br)
# hwriteLatex(as.latex("\{ 26.119 < \sum_{i=1}^n(X_i-\bar{X})^2\}
# \bigcup\ \{ 5.629 > \sum_{i=1}^n (X_i-\bar{X})^2 \}.",
# inline = FALSE, label = "anequationlabel"),
# page = p,
# tr.attributes = "bgcolor = 'gray'",
# td.attributes = c("width = '50'",
# "align = 'center' bgcolor = 'yellow'",
# "align = 'right' width = '50'"))
# closePage(p)
# ### Open a web browser and examine the resulting file
# if (interactive()) try(browseURL(fileName))
# ## End(Not run)
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