summary {base} | R Documentation

## 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, ...)

    ## 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, ...)

### 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.

### 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`.

### 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.

### References

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

### See Also

`anova`, `summary.glm`, `summary.lm`.

### 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))

[Package base version 2.15.1 Index]