xy.coords {grDevices} | R Documentation |

`xy.coords`

is used by many functions to obtain
x and y coordinates for plotting. The use of this common mechanism
across all relevant **R** functions produces a measure of consistency.

xy.coords(x, y = NULL, xlab = NULL, ylab = NULL, log = NULL, recycle = FALSE)

`x, y` |
the x and y coordinates of a set of points.
Alternatively, a single argument `x` can be provided. |

`xlab,ylab` |
names for the x and y variables to be extracted. |

`log` |
character, `"x"` , `"y"` or both, as for
`plot` . Sets negative values to `NA` and
gives a warning. |

`recycle` |
logical; if `TRUE` , recycle (`rep` )
the shorter of `x` or `y` if their lengths differ. |

An attempt is made to interpret the arguments `x`

and `y`

in
a way suitable for bivariate plotting (or other bivariate procedures).

If `y`

is `NULL`

and `x`

is a

- formula:
- of the form
`yvar ~ xvar`

.`xvar`

and`yvar`

are used as x and y variables. - list:
- containing components
`x`

and`y`

, these are used to define plotting coordinates. - time series:
- the x values are taken to be
`time(x)`

and the y values to be the time series. - matrix or
`data.frame`

with two or more columns: - the first is assumed to contain the x values and the
second the y values.
*Note*that is also true if`x`

has columns named`"x"`

and`"y"`

; these names will be irrelevant here.

In any other case, the `x`

argument is coerced to a vector and
returned as **y** component where the resulting `x`

is just
the index vector `1:n`

. In this case, the resulting `xlab`

component is set to `"Index"`

.

If `x`

(after transformation as above) inherits from class
`"POSIXt"`

it is coerced to class `"POSIXct"`

.

A list with the components

`x` |
numeric (i.e., `"double"` ) vector of abscissa values. |

`y` |
numeric vector of the same length as `x` . |

`xlab` |
`character(1)` or `NULL` , the ‘label’ of
`x` . |

`ylab` |
`character(1)` or `NULL` , the ‘label’ of
`y` . |

`plot.default`

, `lines`

, `points`

and `lowess`

are examples of functions which use this mechanism.

xy.coords(stats::fft(c(1:10)), NULL) with(cars, xy.coords(dist ~ speed, NULL)$xlab ) # = "speed" xy.coords(1:3, 1:2, recycle=TRUE) xy.coords(-2:10,NULL, log="y") ##> warning: 3 y values <=0 omitted ..

[Package *grDevices* version 2.5.0 Index]