str {base}

R Documentation

Compactly Display the Structure of an Arbitrary R Object

Description

Compactly display the internal structure of an R object, a “diagnostic” function and an alternative to summary (and to some extent, dput). Ideally, only one line for each “basic” structure is displayed. It is especially well suited to compactly display the (abbreviated) contents of (possibly nested) lists. The idea is to give reasonable output for any R object. It calls args for (non-primitive) function objects.

ls.str and lsf.str are useful “versions” of ls, calling str on each object. They are not foolproof and should rather not be used for programming, but are provided for their usefulness.

Usage

str(object, ...)
str.data.frame(object, ...)
str.default(object, max.level = 0, vec.len = 4, digits.d = 3,
    nchar.max = 128, give.attr = TRUE, give.length = TRUE,
    wid = getOption("width"), nest.lev = 0,
    indent.str = paste(rep(" ", max(0, nest.lev + 1)), collapse = ".."),
    ...)

 ls.str(pos = 1, pattern, ..., mode = "any",
        max.level = 1, give.attr = FALSE)
lsf.str(pos = 1, pattern, ...)

Arguments

object	any R object about which you want to have some information.
max.level	maximal level of nesting which is applied for displaying nested structures, e.g., a list containing sub lists. Default 0: Display all nesting levels.
vec.len	numeric (>= 0) indicating how many “first few” elements are displayed of each vector. The number is multiplied by different factors (from .5 to 3) depending on the kind of vector. Default 4.
digits.d	number of digits for numerical components (as for print).
nchar.max	maximal number of characters to show for character strings. Longer strings are truncated, see longch example below.
give.attr	logical; if TRUE (default), show attributes as sub structures.
give.length	logical; if TRUE (default), indicate length (as [1:...]).
wid	the page width to be used. The default is the currently active options("width").
nest.lev	current nesting level in the recursive calls to str.
indent.str	the indentation string to use.
...	potential further arguments (required for Method/Generic reasons).

For ls.str and lsf.str:

pos	integer indicating search path position.
pattern	regular expression passed to ls. Only names matching pattern are considered.
mode	character specifying the mode of objects to consider. Passed to exists and get.

Value

str does not return anything, for efficiency reasons. The obvious side effect is output to the terminal.

ls.str and lsf.str invisibly return a character vector of the matching names, similarly to ls.

Author(s)

Martin Maechler maechler@stat.math.ethz.ch since 1990.

See Also

summary, args.

Examples

## The following examples show some of `str' capabilities
str(1:12)
str(ls)
str(args)#- more useful than  args(args) !
data(freeny); str(freeny)
str(str)
str(.Machine, digits = 20)
str( lsfit(1:9,1:9))
str( lsfit(1:9,1:9),  max =1)
op <- options(); str(op)#- save first; otherwise internal options() is used.
need.dev <- !exists(".Device") || is.null(.Device)
if(need.dev) postscript()
str(par()); if(need.dev) graphics.off()

nchar(longch <- paste(rep(letters,100), collapse=""))
str(longch)
str(longch, nchar.max = 52)

lsf.str()#- how do the functions look like which I am using?
ls.str(mode = "list")#- what are the structured objects I have defined?
## which base functions have "file" in their name ?
lsf.str(pos = length(search()), pattern = "file")

---