help.search package:utils R Documentation _S_e_a_r_c_h _t_h_e _H_e_l_p _S_y_s_t_e_m _D_e_s_c_r_i_p_t_i_o_n: Allows for searching the help system for documentation matching a given character string in the (file) name, alias, title, concept or keyword entries (or any combination thereof), using either fuzzy matching or regular expression matching. Names and titles of the matched help entries are displayed nicely formatted. _U_s_a_g_e: help.search(pattern, fields = c("alias", "concept", "title"), apropos, keyword, whatis, ignore.case = TRUE, package = NULL, lib.loc = NULL, help.db = getOption("help.db"), verbose = getOption("verbose"), rebuild = FALSE, agrep = NULL) ??pattern field??pattern _A_r_g_u_m_e_n_t_s: pattern: a character string to be matched in the specified fields. If this is given, the arguments 'apropos', 'keyword', and 'whatis' are ignored. fields: a character vector specifying the fields of the help data bases to be searched. The entries must be abbreviations of '"name"', '"title"', '"alias"', '"concept"', and '"keyword"', corresponding to the help page's (file) name, its title, the topics and concepts it provides documentation for, and the keywords it can be classified to. apropos: a character string to be matched in the help page topics and title. keyword: a character string to be matched in the help page 'keywords'. 'Keywords' are really categories: the standard categories are listed in file 'RHOME/doc/KEYWORDS' (see also the example) and some package writers have defined their own. If 'keyword' is specified, 'agrep' defaults to 'FALSE'. whatis: a character string to be matched in the help page topics. ignore.case: a logical. If 'TRUE', case is ignored during matching; if 'FALSE', pattern matching is case sensitive. package: a character vector with the names of packages to search through, or 'NULL' in which case _all_ available packages in the library trees specified by 'lib.loc' are searched. lib.loc: a character vector describing the location of R library trees to search through, or 'NULL'. The default value of 'NULL' corresponds to all libraries currently known. help.db: a character string giving the file path to a previously built and saved help data base, or 'NULL'. verbose: logical; if 'TRUE', the search process is traced. rebuild: a logical indicating whether the help data base should be rebuilt. This will be done automatically if 'lib.loc' or the search path is changed, or if 'package' is used and a value is not found. agrep: if 'NULL' (the default unless 'keyword' is used) and the character string to be matched consists of alphanumeric characters, whitespace or a dash only, approximate (fuzzy) matching via 'agrep' is used unless the string has fewer than 5 characters; otherwise, it is taken to contain a regular expression to be matched via 'grep'. If 'FALSE', approximate matching is not used. Otherwise, one can give a numeric or a list specifying the maximal distance for the approximate match, see argument 'max.distance' in the documentation for 'agrep'. field: a single value of 'fields' to search. _D_e_t_a_i_l_s: Upon installation of a package, a pre-built help.search index is serialized as 'hsearch.rds' in the 'Meta' directory (provided the package has any help pages). These files are used to create the data base. The arguments 'apropos' and 'whatis' play a role similar to the Unix commands with the same names. Searching with 'agrep = FALSE' will be several times faster than the default. If possible, the help data base is saved in memory or (if memory limits have been set: see 'mem.limits') to a file in the session temporary directory for use by subsequent calls in the session. Note that currently the aliases in the matching help files are not displayed. Matching by 'agrep' is by bytes even in multi-byte locales: character-by-character matching will be too slow with a thousand or more packages. As with '?', in '??' the pattern may be prefixed with a package name followed by '::' or ':::' to limit the search to that package. _V_a_l_u_e: The results are returned in a list object of class '"hsearch"', which has a print method for nicely formatting the results of the query. This mechanism is experimental, and may change in future versions of R. In R.app on Mac OS X, this will show up a browser with selectable items. On exiting this browser, the help pages for the selected items will be shown in separate help windows. The internal format of the class is undocumented and subject to change. _S_e_e _A_l_s_o: 'help'; 'help.start' for starting the hypertext (currently HTML) version of R's online documentation, which offers a similar search mechanism. 'RSiteSearch' to access an on-line search of R resources. 'apropos' uses regexps and has nice examples. _E_x_a_m_p_l_e_s: help.search("linear models") # In case you forgot how to fit linear # models help.search("non-existent topic") ??utils::help # All the topics matching "help" in the utils package ## Not run: help.search("print") # All help pages with topics or title # matching 'print' help.search(apropos = "print") # The same help.search(keyword = "hplot") # All help pages documenting high-level # plots. file.show(file.path(R.home("doc"), "KEYWORDS")) # show all keywords ## Help pages with documented topics starting with 'try'. help.search("\\btry", fields = "alias") ## End(Not run)