Question

a. Use positional matching with seq to create a sequence of values between −4 and 4 that progresses in steps of 0.2.

b. In each of the following lines of code, identify which style of argument matching is being used: exact, partial, positional, or mixed. If mixed, identify which arguments are specified in each style.

i array(8:1,dim=c(2,2,2))

ii rep(1:2,3)

iii seq(from=10,to=8,length=5)

iv sort(decreasing=T,x=c(2,1,1,2,0.3,3,1.3))

v which(matrix(c(T,F,T,T),2,2))

vi which(matrix(c(T,F,T,T),2,2),a=T)

c. Suppose you explicitly ran the plotting function plot.default and supplied values to arguments tagged type , pch , xlab , ylab , lwd , lty , and col . Use the function documentation to determine which of these arguments fall under the umbrella of the ellipsis.

Answer 1

a.

R code to to create a sequence of values between −4 and 4 that progresses in steps of 0.2 using positional matching is,

seq(-4,4,0.2)

b.

Exact matching - Each argument tag is written out in full

Partial - Identify arguments with abbreviated tag

Positional - Supply arguments without tag and R interprets by position

Mixed - Mixture of the three styles

i array(8:1,dim=c(2,2,2))

The syntax of array is,

array(data = NA, dim = length(data), dimnames = NULL)

So, this is a mixed type.

data is positional argument

dim is Exact matching

ii rep(1:2,3)

The syntax of rep is,

rep(x, times)

So, this is a positional type.

iii seq(from=10,to=8,length=5)

Each argument has its full name.

So, this is a Exact matching type.

iv sort(decreasing=T,x=c(2,1,1,2,0.3,3,1.3))

The syntax of Sort is,

sort(x, decreasing = FALSE)

Here True is abbreviated as T, but x is given as full argument name.

So, this is a mixed type.

decreasing is Partial

x is Exact matching

v which(matrix(c(T,F,T,T),2,2))

The syntax of which is,

which(x, arr.ind = FALSE, useNames = TRUE, ind)

All arguments are recognized by position.

So, this is a Positional type.

vi which(matrix(c(T,F,T,T),2,2),a=T)

All arguments are recognized by position.

Here True is abbreviated as T

So, this is a Mixed type.

c.

The syntax of plot is,

plot(x, y = NULL, type = "p",  xlim = NULL, ylim = NULL,
     log = "", main = NULL, sub = NULL, xlab = NULL, ylab = NULL,
     ann = par("ann"), axes = TRUE, frame.plot = axes,
     panel.first = NULL, panel.last = NULL, asp = NA, ...)

So, type, xlab, ylab are present in the plot function.

Hence,   pch , lwd , lty , and col will fall under the umbrella of the ellipsis (...)