143 lines
3.0 KiB
R
143 lines
3.0 KiB
R
#' ---
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#' title: "Getting help in R"
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#' date: "2021-11-24"
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#' author: "Jose"
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#' output:
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#' html_document:
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#' code_folding: show
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#' toc: yes
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#' toc_float:
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#' smooth_scroll: true
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#' df_print: paged
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#' highlight: zenburn
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#' ---
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#' removing objects
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#'
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rm(list = ls())
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#' ## Common ways of getting help when working with R
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#'
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#' ## Find the formal arguments in a function
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#'
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formalArgs(help)
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formalArgs(table)
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#' ### Use "help", "help.search" or "find" when need to search for some terms
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#'
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#' Use "help.start" to view all R documentation
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help.start()
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#' Within R use the "?" question symbol before any command and run the code
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#' to get help on that function.
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#'
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#' Getting help with "dput()" and "Compare" functions:
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#'
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?dput
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?Compare
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#' Ask about control-flow constructs in R
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help("if")
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#' Information about extract or replace function
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help("[[")
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#' Help on "Quotes"
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help(Quotes)
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#' Use "help.search" to find functions matching any word
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help.search("download file")
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#' ### "find" can be used to know which package contains a function
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find("table")
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#' This will return nothing, because the package should be loaded in the session
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#' in order to "find" the function
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find("count")
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#' Then, after loading the package that contains the function it should run
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#' without any problem
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library(dplyr)
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find("count")
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#' Unload a package from the environment
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#'
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detach("package:dplyr", unload = TRUE)
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#' ### "apropos" gives the name of objects containing the characters passed to
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#' the function.
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#'
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#' Remember that wihin R (almost) everything that exist is an object and everything
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#' that happens is a function. Thus apropos will find any object (including
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#' functions) within the session matching the word.
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count_testing <- c(1,2)
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apropos("count")
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#' ## Examples and demostration of functions
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#'
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#' ### Examples included in packages documentation
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#'
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#' The function to show examples of any functions is called "example":
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example(glm)
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#' To extract examples of any function, the package containing the function should
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#' be loaded in the session:
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#'
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library(data.table)
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#' Check some examples on how to use the function ".N" in the "data.table" package
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example(.N)
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library(dplyr)
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example(case_when)
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#' ### Using "demo()"
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demo(graphics)
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#' ## Searching in packages
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#'
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#' Obtain help in packages
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library(help = data.table)
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#' ## Finding objects within a package and checking documentation
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#' ### Finding objects
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#'
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#' Here we use "grep" to look for objects within the package "data.table".
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#' The function "search" is applied to look for R objects, thus the function
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#' will return the names of every function within the package
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#'
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library(data.table)
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objects(grep("data.table", search()))
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#' Take a look to the objects in the base package:
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#'
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obase <- objects(grep("base", search()))
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head(obase, n=10)
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#' ### List vignettes in a package
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vignette(package = "data.table")
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browseVignettes("data.table")
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vignette("datatable-faq")
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#' End
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#' You can export this document as html using "rmarkdown":
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#'
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#' rmarkdown::render("./help_r.R")
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