summary( )

Summarize an object. summary() is a generic function in base R.

Required Library

# summary() is in base R, loaded by default — no package installation needed

summary(object, ...)

summary(object) returns a compact summary of an object. Because summary() is generic, output depends on the class of the object.

Why does summary() look different each time?

summary() dispatches different methods based on object type.

Numeric vector: min, quartiles, median, mean, max
Data frame: summary for each column
Linear model (lm): residuals, coefficients, residual standard error, R-squared, F-statistic

Summarize a numeric vector

Summarize each column in a data frame

Summarize an lm() model and extract R-squared

Compare summary() and coef() for a model

Required arguments must be included when using a function while optional arguments can be included on demand.

object — object to summarize any R object Required

The object for which summary information should be produced.

summary(x)
summary(df)
summary(model)

Data Types: numeric, factor, data frame, model object, and many others

… — method-specific options various Optional

Additional arguments passed to class-specific summary methods. Most common beginner use is simply summary(object) with no extra arguments.

Data Types: depends on object class