# plot.stepfun

##### Plot Step Functions

Method of the generic `plot`

for `stepfun`

objects and utility for plotting piecewise constant functions.

- Keywords
- hplot

##### Usage

```
# S3 method for stepfun
plot(x, xval, xlim, ylim = range(c(y, Fn.kn)),
xlab = "x", ylab = "f(x)", main = NULL,
add = FALSE, verticals = TRUE, do.points = (n < 1000),
pch = par("pch"), col = par("col"),
col.points = col, cex.points = par("cex"),
col.hor = col, col.vert = col,
lty = par("lty"), lwd = par("lwd"), …)
```# S3 method for stepfun
lines(x, …)

##### Arguments

- x
an R object inheriting from

`"stepfun"`

.- xval
numeric vector of abscissa values at which to evaluate

`x`

. Defaults to`knots(x)`

restricted to`xlim`

.- xlim, ylim
limits for the plot region: see

`plot.window`

. Both have sensible defaults if omitted.- xlab, ylab
labels for x and y axis.

- main
main title.

- add
logical; if

`TRUE`

only*add*to an existing plot.- verticals
logical; if

`TRUE`

, draw vertical lines at steps.- do.points
logical; if

`TRUE`

, also draw points at the (`xlim`

restricted) knot locations. Default is true, for sample size \(< 1000\).- pch
character; point character if

`do.points`

.- col
default color of all points and lines.

- col.points
character or integer code; color of points if

`do.points`

.- cex.points
numeric; character expansion factor if

`do.points`

.- col.hor
color of horizontal lines.

- col.vert
color of vertical lines.

- lty, lwd
line type and thickness for all lines.

- …

##### Value

A list with two components

abscissa (x) values, including the two outermost ones.

y values ‘in between’ the `t[]`

.

##### See Also

`ecdf`

for empirical distribution functions as
special step functions,
`approxfun`

and `splinefun`

.

##### Examples

`library(stats)`

```
# NOT RUN {
require(graphics)
y0 <- c(1,2,4,3)
sfun0 <- stepfun(1:3, y0, f = 0)
sfun.2 <- stepfun(1:3, y0, f = .2)
sfun1 <- stepfun(1:3, y0, right = TRUE)
tt <- seq(0, 3, by = 0.1)
op <- par(mfrow = c(2,2))
plot(sfun0); plot(sfun0, xval = tt, add = TRUE, col.hor = "bisque")
plot(sfun.2);plot(sfun.2, xval = tt, add = TRUE, col = "orange") # all colors
plot(sfun1);lines(sfun1, xval = tt, col.hor = "coral")
##-- This is revealing :
plot(sfun0, verticals = FALSE,
main = "stepfun(x, y0, f=f) for f = 0, .2, 1")
for(i in 1:3)
lines(list(sfun0, sfun.2, stepfun(1:3, y0, f = 1))[[i]], col = i)
legend(2.5, 1.9, paste("f =", c(0, 0.2, 1)), col = 1:3, lty = 1, y.intersp = 1)
par(op)
# Extend and/or restrict 'viewport':
plot(sfun0, xlim = c(0,5), ylim = c(0, 3.5),
main = "plot(stepfun(*), xlim= . , ylim = .)")
##-- this works too (automatic call to ecdf(.)):
plot.stepfun(rt(50, df = 3), col.vert = "gray20")
# }
```

*Documentation reproduced from package stats, version 3.5.2, License: Part of R 3.5.2*