# summary: Object Summaries

## Description

`summary`

is a generic function used to produce result summaries
of the results of various model fitting functions. The function
invokes particular `methods`

which depend on the
`class`

of the first argument.
## Usage

summary(object, ...)

"summary"(object, ..., digits = max(3, getOption("digits")-3))
"summary"(object, maxsum = 7, digits = max(3, getOption("digits")-3), ...)

"summary"(object, maxsum = 100, ...)

"summary"(object, ...)

## Arguments

object

an object for which a summary is desired.

maxsum

integer, indicating how many levels should be shown for
`factor`

s. digits

integer, used for number formatting with
`signif()`

(for `summary.default`

) or
`format()`

(for `summary.data.frame`

). ...

additional arguments affecting the summary produced.

## Value

The form of the value returned by `summary`

depends on the
class of its argument. See the documentation of the particular
methods for details of what is produced by that method.The default method returns an object of class
`c("summaryDefault", "table")`

which has a specialized
`print`

method. The `factor`

method returns an
integer vector.The matrix and data frame methods return a matrix of class
`"table"`

, obtained by applying `summary`

to each
column and collating the results.

## Details

For `factor`

s, the frequency of the first `maxsum - 1`

most frequent levels is shown, and the less frequent levels are
summarized in `"(Others)"`

(resulting in at most `maxsum`

frequencies). The functions `summary.lm`

and `summary.glm`

are examples
of particular methods which summarize the results produced by
`lm`

and `glm`

.

## References

Chambers, J. M. and Hastie, T. J. (1992)
*Statistical Models in S*.
Wadsworth & Brooks/Cole.
## Examples

summary(attenu, digits = 4) #-> summary.data.frame(...), default precision
summary(attenu $ station, maxsum = 20) #-> summary.factor(...)
lst <- unclass(attenu$station) > 20 # logical with NAs
## summary.default() for logicals -- different from *.factor:
summary(lst)
summary(as.factor(lst))