apropos: Find Objects by (Partial) Name

Description

apropos() returns a character vector giving the names of objects in the search list matching (as a regular expression) what.

find() returns where objects of a given name can be found.

Usage

apropos(what, where = FALSE, ignore.case = TRUE, mode = "any")
find(what, mode = "any", numeric = FALSE, simple.words = TRUE)

Arguments

what

character string. For simple.words = FALSE the name of an object; otherwise a regular expression to match object names against.

where, numeric

a logical indicating whether positions in the search list should also be returned

ignore.case

logical indicating if the search should be case-insensitive, TRUE by default.

mode

character; if not "any", only objects whose mode equals mode are searched.

simple.words

logical; if TRUE, the what argument is only searched as a whole word.

Value

For apropos, a character vector sorted by name. For where = TRUE this has names giving the (numerical) positions on the search path.

For find, either a character vector of environment names or (for numeric = TRUE) a numerical vector of positions on the search path with names the names of the corresponding environments.

Details

If mode != "any" only those objects which are of mode mode are considered.

find is a different user interface for a similar task to apropos. By default (simple.words == TRUE), only whole names are matched. Unlike apropos, matching is always case-sensitive.

Unlike the default behaviour of ls, names which begin with a . are included (and these are often ‘internal’ objects --- as from R 3.4.0 most such are excluded).

Examples

Run this code

# NOT RUN {
require(stats)

# }
# NOT RUN {
<!-- %% some of these have enormous output that varies a lot by version -->
# }
# NOT RUN {
apropos("lm")
# }
# NOT RUN {
apropos("GLM")                      # several
apropos("GLM", ignore.case = FALSE) # not one
apropos("lq")

cor <- 1:pi
find("cor")                         #> ".GlobalEnv"   "package:stats"
find("cor", numeric = TRUE)                     # numbers with these names
find("cor", numeric = TRUE, mode = "function")  # only the second one
rm(cor)

# }
# NOT RUN {
apropos(".", mode="list")  # a long list
# }
# NOT RUN {
# need a DOUBLE backslash '\\' (in case you don't see it anymore)
apropos("\\[")

# }
# NOT RUN {
# everything % not diff-able
length(apropos("."))

# those starting with 'pr'
apropos("^pr")

# the 1-letter things
apropos("^.$")
# the 1-2-letter things
apropos("^..?$")
# the 2-to-4 letter things
apropos("^.{2,4}$")

# the 8-and-more letter things
apropos("^.{8,}$")
table(nchar(apropos("^.{8,}$")))
# }

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