R: Set Top-level R Markdown YAML Fields

yml_author {ymlthis}

R Documentation

Set Top-level R Markdown YAML Fields

Description

These functions add common top-level YAML fields for R Markdown documents, such as author, date, and title. Each takes a yml object and adds fields related to the function, as well as checking for duplicate fields and (where possible) checking for valid entries. yml_toplevel() is a catch-all function that will take any named R object and put in the top level of the YAML; it checks for duplicate fields but is unable to validate the input beyond that it is valid YAML syntax. Some R Markdown templates allow for additional variations of the YAML here. For instance, the distill package adds url and affiliation_url to the author field (see yml_distill_author, which wraps yml_author). Several ⁠yml_*()⁠ functions also contain ... which allow for these unique fields.

Usage

yml_author(.yml, name = NULL, affiliation = NULL, email = NULL, ...)

yml_date(.yml, date = NULL, format = "")

yml_title(.yml, title)

yml_subtitle(.yml, subtitle)

yml_abstract(.yml, abstract)

yml_keywords(.yml, keywords)

yml_subject(.yml, subject)

yml_description(.yml, description)

yml_category(.yml, category)

yml_lang(.yml, lang)

yml_toplevel(.yml, ...)

Arguments

`.yml`	a `yml` object created by `yml()`, `as_yml()`, or returned by a `⁠yml_*()⁠` function
`name`	A character vector, name of the author(s)
`affiliation`	The author's affiliation; must match length of `name`, e.g. if `name` has length of two, `affiliation` must as well; use `NA` if you don't want to include an affiliation for a given author.Note that not all formats support the `affiliation` field.
`email`	The author email address. Note that not all formats support the `email` field.
`...`	additional named R objects, such as characters or lists, to transform into YAML
`date`	The date; by default this is "`r format(Sys.Date())`", which will populate the date automatically.
`format`	When the default `date` is used, the format passed to `format.Date()`.
`title`	A character vector, the title of the document
`subtitle`	A character vector, the subtitle of the document. Not all R Markdown formats use subtitles, so it may depend on what you use in the output field (see `yml_output()`). It is available in `pdf_document()`, `html_document()`, and `word_document()` by default.
`abstract`	A character vector, the abstract. Long character vectors are automatically wrapped using valid YAML syntax. This field is not available in all output formats; it is available in `pdf_document()` and `html_document()` by default.
`keywords`	A character vector of keywords. This field is not available in all output formats; it is available in `pdf_document()`, `html_document()`, `word_document()`, `odt_document()`, and `powerpoint_presentation()` by default.
`subject`	A character vector, the subject of the document. This field is not available in all output formats; it is available in `pdf_document()`, `html_document()`, `word_document()`, `odt_document()`, and `powerpoint_presentation()` by default.
`description`	A character vector, a description of the document. This field is not available in all output formats; it is available in `word_document()`, `odt_document()`, and `powerpoint_presentation()` by default.
`category`	A character vector, the category of the document. This field is not available in all output formats; it is available in `word_document()` and `powerpoint_presentation()` by default.
`lang`	The document language using IETF language tags such as "en" or "en-US". The Language subtag lookup tool can help find the appropriate tag.

Value

a yml object

Examples

yml_empty() %>%
  yml_author("Yihui Xie") %>%
  yml_date("02-02-2002") %>%
  yml_title("R Markdown: An Introduction") %>%
  yml_subtitle("Introducing ymlthis") %>%
  yml_abstract("This paper will discuss a very important topic") %>%
  yml_keywords(c("r", "reproducible research")) %>%
  yml_subject("R Markdown") %>%
  yml_description("An R Markdown reader") %>%
  yml_category("r") %>%
  yml_lang("en-US")