qqnorm2s {Ecfun}R Documentation

Normal Probability Plot with Multiple Lines and Multiple Symbols


Create a normal probability plot with one line for each y variable or each data.frame in a list data. with different plotting symbols for the values of z.

To create a normal probability plot with one y variable split on a link{factor} or character variable x, see qqnorm2t.

qqnorm2s produces an object of class qqnorm2s, whose plot method produces the plot.


qqnorm2s(y, z=NULL, data., plot.it=TRUE, 
    datax=TRUE, outnames=NULL, pch=NULL, 
    col=c(1:4, 6), legend.=NULL, ...)
## S3 method for class 'qqnorm2s'
plot(x, y, ...)



a character vector of names of columns of data. for which normal probability plots are desired. data. is either a data.frame or a list of data.frames of the same length as y, with y[i] being the name of a column of the data.frame data.[[i]]. z is a similar character vector of names of columns of data., which identify symbols for plotting different points in a normal probability plot.

The lengths of y, and z must match the number of data.frames in data.; if not, the lengths of the shorter are replicated to the length of the longest before computations begin.

For plot.qqnorm2s, y is ignored; it is included, because the generic plot function requires it.


A character vector giving the names of columns of data. to indicate different plotting symbols. z should be the same length as y and must equal the number of data.frames in the list data. of data.frames. If not, the shorter are replicated to the length of the longer.


a data.frame or a list of data.frames with columns named in y and z.


logical: Should the result be plotted?


The datax argument of qqnorm: If TRUE, the data are displayed on the horizontal rather than the vertical axis. (The default value for datax is the opposite of that for qqnorm.)


Names for the components of the qqnorm2s object returned by the qqnorm2s function.


a named vector of the plotting symbols to be used with names corresponding to the levels of z.

By default, if z takes levels FALSE and TRUE (or 0 and 1), pch=c(4, 1) to plot a "x" for FALSE and "o" for TRUE.

If z assumes integer values between 0 and 255, by default, the symbols are chosen as described with points.

Otherwise, by default, z is coerced to character, and the result is plotted.

If pch is provided, it must either have names corresponding to levels of z, or z must be integers between 1 and length(pch).


A vector indicating the colors corresponding to each element of y. Defaults to rep(c(1:4, 6), length=length(y)), with 1:4 and 6 being black, red, green, blue, and pink.


an object of class qqnorm2.


A list with components pch and col providing information for legend to identify the plotting symbols (pch) and colors (col).

By default, pch = list(x='right', legend=names(qq2s[[1]][['pch']]), pch=qq2s[[1]][['pch']]), where qq2s is described below in details.

Similarly, by default, lines = list(x='bottomright', legend=y, lty=1, pch=NA, col=qq2s[[1]][['col']]).


Optional arguments.

For plot.qqnorm2s, they are passed to plot.

For qqnorm2s, they are passed to qqnorm2 and to plot.qqnorm2s.


For qqnorm2s:

1. Create qq2s = a list of objects of class qqnorm2

2. Add legend. to qq2s.

3. class(qq2s) <- 'qqnorm2s'

4. if(plot.it)plot(qq2s, ...)

5. Silently return(qq2s).

For plot.qqnorm2s, create a plot with one line for each variable named in y.


qqnorm2s returns a named list with components of class qqnorm2 with names = y with each component having an additional component col plus one called "legend.".


Spencer Graves

See Also

qqnorm2 plot


## One data.frame
tstDF2 <- data.frame(y=1:3, y2=3:5, 
    z2=c(TRUE, TRUE, FALSE),
    z3=c('tell', 'me', 'why'), 
    z4=c(1, 2.4, 3.69) )
# produce the object and plot it
Qn2 <- qqnorm2s(c('y', 'y2'), 'z2', tstDF2)

# plot the object previously created

# Check the object
qy <- with(tstDF2, qqnorm2(y, z2, type='b'))
qy$col <- 1
qy2 <- with(tstDF2, qqnorm2(y2, z2, type='b'))
qy2$col <- 2
legend. <- list(
      legend=c('FALSE', 'TRUE'),
      pch=c('FALSE'=4, 'TRUE'= 1)),
      legend=c('y', 'y2'), lty=1, col=1:2))
Qn2. <- list(y=qy, y2=qy2, legend.=legend.)
class(Qn2.) <- 'qqnorm2s'

all.equal(Qn2, Qn2.)

## Two data.frames
tstDF2b <- tstDF2
tstDF2b$y <- c(0.1, 0.1, 9)
Qn2b <- qqnorm2s('y', 'z2', 
    list(tstDF2, tstDF2b), 
    outnames=c('ok', 'oops'), log='x' )
## Split one data.frame 
tstDF2. <- rbind(cbind(tstDF2, z1=1), 
                 cbind(tstDF2b, z1=2) )
Qn2. <- qqnorm2s('y', 'z1', tstDF2.)
# Plot has only one line, because only 1 y variable.  
## Two data.frames without z
Qn2.0 <- qqnorm2s('y', 
    data.=list(tstDF2, tstDF2b), 
    outnames=c('ok', 'oops'), log='x' )

[Package Ecfun version 0.3-2 Index]