Read a child document, render it based on the file extension, which can be
.R, .Rmd, .md, or .tex, and place the resulting text into the main document.
Acts as a wrapper for knitr::knit_child().
read_child(filein)base::cat() is used to print output to the screen if you run this function
on its own or to a resulting rendered file if called within an .Rmd file,
where the latter is more likely.
The input file will be knitr::knit() quietly using internal code to set
quiet = TRUE to suppress the progress bar and messages output from
knitr. All R objects will be available in the global environment after
the file is rendered. That is, you will be able to inspect all R objects
that are created within filein after you attempt to render parent file.
This is helpful when you receive and error message or you just want to
investigate the structure or results of an object made during the process.
For example, if the child document includes the creation of a data frame
named test, then you could inspect the data frame after rendering the
document, e.g., dim(test).
Child documents are extremely helpful for when you want to share scripts or
text across multiple assessments documents, e.g., north and south area
models for a given species. In this situation, you could have two folders
that store the each store an individual assessment and a third folder that
stores text that is common to both documents. Then, you would call this
common text within each of the Introduction sections using
read_child(file.path("..", "commonintro.Rmd")) inside of an R chunk. See
the example section for more details.
if (FALSE) { # \dontrun{
# See below for how to include this function in your .Rmd file.
# Note that the label for the R chunk (e.g., child_firstexample)
# needs to be unique, that is each time you copy and paste this code
# you must change the label to be a new value that is not used elsewhere.
# This example will look for a file called commonintro.Rmd inside a
# folder called common_text that is located just outside of your current
# directory.
#
# ```{r child_firstexample}
# read_child(filein = file.path("..", "common_text", "commonintro.Rmd"))
# ```
} # }