R/equation.R
equation.RdExtract or create a 'LaTeX' equation to describe a model, or directly from
'LaTeX' code. All objects supported by extract_eq() are also supported by
the default method description. If labels (and units) are defined as
attributes to the data, they are automatically used in the equation in place
of the variable names.
equation(object, ...)
# Default S3 method
equation(
object,
auto.labs = TRUE,
origdata = NULL,
labs = NULL,
swap_var_names = NULL,
...
)
# S3 method for class 'character'
equation(object, ...)
eq__(object, ...)
eq_(object, ...)
# S3 method for class 'inline_equation'
print(x, ...)An object with a model whose the equation is constructed. If a
character object is provided, it is concatenated into a single
character string and the equation class, otherwise it is not
transformed (it is supposed to be a valid 'LaTeX' equation). Remember that
backslashes must be doubled in regular R strings, or use the r"(...)"
notation, which may be more comfortable here, see examples.
Further parameters passed to extract_eq().
If TRUE (by default), use labels (and units) automatically
from data or origdata=.
The original data set this model was fitted to. By default it
is NULL and no label is used.
Labels to change the names of elements in the term column of
the table. By default it is NULL and no term is changed.
Change the variable names for these values, regardless
of the values in auto.labs= or labs= that are ignored if this argument
is used. Provide a named character string with name being the variables and
strings the new names. You can use ^ or _ to indicate next character,
or next integer should be super- or subscript in the equation.
An inline_equation object generated by eq_() or eq__().
An object of class c("equation", "character").
There are slight differences between equation(), eq_() and eq__():
equation() returns a string with 'LaTeX' code and prints 'LaTeX' code at
the R console.
eq_() returns the 'LaTeX' code surrounded by a dollar sign $...$ and is
suitable to build inline equations in R Markdown/Quarto documents by using
inline R code. It prints the rendered inline equation in the RStudio
Viewer or in the browser. So it is advised to rapidly preview the
resulting equation.
eq__() returns the 'LaTeX' code not surrounded by dollar signs in a
single character string. It also prints the rendered inline equation in
the RStudio Viewer or in the browser.
It should be used in an R inline chunk inside a $$...$$
construct in a Markdown text. The result is a display equation that can
also be cross referenced in Quarto in the usual way if you label it, e.g.,
you use $$...$$ {#eq-label}.
iris_lm <- lm(data = iris, Petal.Length ~ Sepal.Length + Species)
summary(iris_lm)
#>
#> Call:
#> lm(formula = Petal.Length ~ Sepal.Length + Species, data = iris)
#>
#> Residuals:
#> Min 1Q Median 3Q Max
#> -0.76390 -0.17875 0.00716 0.17461 0.79954
#>
#> Coefficients:
#> Estimate Std. Error t value Pr(>|t|)
#> (Intercept) -1.70234 0.23013 -7.397 1.01e-11 ***
#> Sepal.Length 0.63211 0.04527 13.962 < 2e-16 ***
#> Speciesversicolor 2.21014 0.07047 31.362 < 2e-16 ***
#> Speciesvirginica 3.09000 0.09123 33.870 < 2e-16 ***
#> ---
#> Signif. codes: 0 ‘***’ 0.001 ‘**’ 0.01 ‘*’ 0.05 ‘.’ 0.1 ‘ ’ 1
#>
#> Residual standard error: 0.2826 on 146 degrees of freedom
#> Multiple R-squared: 0.9749, Adjusted R-squared: 0.9744
#> F-statistic: 1890 on 3 and 146 DF, p-value: < 2.2e-16
#>
equation(iris_lm)
#> $$
#> \operatorname{Petal.Length} = \alpha + \beta_{1}(\operatorname{Sepal.Length}) + \beta_{2}(\operatorname{Species}_{\operatorname{versicolor}}) + \beta_{3}(\operatorname{Species}_{\operatorname{virginica}}) + \epsilon
#> $$
# Providing directly the LaTeX code of the equation (variance of a sample)
equation("S^2_y = \\sum_{i=1}^{n-1} \\frac{(y_i - \\bar{Y})^2}{n}")
#> $$
#> S^2_y = \sum_{i=1}^{n-1} \frac{(y_i - \bar{Y})^2}{n}
#> $$
# Easier to write like this (avoiding the double backslashes):
eq1 <- equation(r"(S^2_y = \sum_{i=1}^{n-1} \frac{(y_i - \bar{Y})^2}{n})")
# Print raw text:
eq1
#> $$
#> S^2_y = \sum_{i=1}^{n-1} \frac{(y_i - \bar{Y})^2}{n}
#> $$
# Get a preview of the equation
eq__(eq1)
# The same function can be used inside a `$$...$$ {#eq-label}` construct in
# R Markdown or Quarto to calcule a display equation that is also recognized
# by the cross referencing system of Quarto.
# Get a string suitable for inclusion inline in R Markdown with `r eq__(eq1)`
# (inside Markdown text and without the dollar signs around it)
# For inline equations in a Markdown text, you are better to use `r eq_(eq1)`
eq_(eq1)