plot.formula {graphics} | R Documentation |

## Formula Notation for Scatterplots

### Description

Specify a scatterplot or add points or lines via a formula.

### Usage

## S3 method for class 'formula':
plot(formula, data = parent.frame(), ..., subset,
ylab = varnames[response], ask = TRUE)
## S3 method for class 'formula':
points(formula, data = parent.frame(), ..., subset)
## S3 method for class 'formula':
lines(formula, data = parent.frame(), ..., subset)

### Arguments

`formula` |
a `formula` , such as `y ~ x` . |

`data` |
a data.frame (or list) from which the variables in
`formula` should be taken. |

`...` |
Further graphical parameters may also be passed as
arguments, see `par` . `horizontal = TRUE`
is also accepted. |

`subset` |
an optional vector specifying a subset of observations
to be used in the fitting process. |

`ylab` |
the y label of the plot(s). |

`ask` |
logical, see `par` . |

### Details

Both the terms in the formula and the `...`

arguments are
evaluated in `data`

enclosed in `parent.frame()`

if
`data`

is a list or a data frame. The terms of the formula and
those arguments in `...`

that are of the same length as
`data`

are subjected to the subsetting specified in
`subset`

. If the formula in `plot.formula`

contains more
than one non-response term, a series of plots of y against each term
is given. A plot against the running index can be specified as
`plot(y ~ 1)`

.

Missing values are not considered in these methods, and in particular
cases with missing values are not removed.

If `y`

is an object (i.e. has a `class`

attribute)
then `plot.formula`

looks for a plot method for that class first.
Otherwise, the class of `x`

will determine the type of the plot.
For factors this will be a parallel boxplot, and argument
`horizontal = TRUE`

can be used (see `boxplot`

).

### Value

These functions are invoked for their side effect of drawing
in the active graphics device.

### See Also

`plot.default`

, `plot.factor`

.

### Examples

op <- par(mfrow=c(2,1))
plot(Ozone ~ Wind, data = airquality, pch=as.character(Month))
plot(Ozone ~ Wind, data = airquality, pch=as.character(Month),
subset = Month != 7)
par(op)

[Package

*graphics* version 2.1.0

Index]