rockchalk (version 1.8.157)

plotSeq: Create sequences for plotting

Description

plotSeq is a convenience for the creation of sequence across the range of a variable. By default, the length of the plotting sequence will be equal to the length of the original sequence. In that case, the only effect is to create an evenly-spaced set of values. If length.out is specified, the user determines the number of elements in plotSeq.

Usage

plotSeq(x, length.out = length(x))

Arguments

x

an R vector variable

length.out

the number of elements in the desired plotting sequence.

Details

The primary intended usage is for the creation of plotting sequences of numeric variables. It takes a variable's range and the fills in evenly spaced steps. If x is a factor variable, the levels will be returned. Uses of this functionality are planned in the future.

See Also

pretty

Examples

#Create a quadratic regression

stde <- 14
x <- rnorm(100, m = 50, s = 10)
y <- 0.2 - 02*x + 0.2*x^2 + stde*rnorm(100)
mod1 <- lm (y ~ poly(x, 2))

plot(x, y, main="The Quadratic Regression")
seqx <- plotSeq(x, length.out = 10)
seqy <- predict(mod1, newdata = data.frame(x = seqx))
lines(seqx, seqy, col = "red")

# Notice the bad result when a plotting sequence is
# not used.
plot(x, y, main = "Bad Plot Result")
seqy <- predict(mod1)
lines(x, seqy, col = "green")