summary {base}R Documentation

Object Summaries


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.


summary(object, ...)

## Default S3 method:
summary(object, ..., digits = max(3, getOption("digits")-3))
## S3 method for class 'data.frame'
summary(object, maxsum = 7,
       digits = max(3, getOption("digits")-3), ...)

## S3 method for class 'factor'
summary(object, maxsum = 100, ...)

## S3 method for class 'matrix'
summary(object, ...)



an object for which a summary is desired.


integer, indicating how many levels should be shown for factors.


integer, used for number formatting with signif() (for summary.default) or format() (for


additional arguments affecting the summary produced.


For factors, 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.


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.


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

See Also

anova, summary.glm, summary.lm.


summary(attenu, digits = 4) #->, default precision
summary(attenu $ station, maxsum = 20) #-> summary.factor(...)

lst <- unclass(attenu$station) > 20 # logical with NAs
## summary.default() for logicals -- different from *.factor:

[Package base version 2.15.0 Index]