stepblock {stepR}  R Documentation 
Constructs an object containing a step function sampled over finitely many values.
stepblock(value, leftEnd = c(1, rightEnd[length(rightEnd)] + 1), rightEnd, x0 = 0)
## S3 method for class 'stepblock'
x[i, j, drop = if(missing(i)) TRUE else if(missing(j)) FALSE else length(j) == 1, ...]
## S3 method for class 'stepblock'
print(x, ...)
## S3 method for class 'stepblock'
plot(x, type = "c", xlab = "x", ylab = "y", main = "Step function", sub = NULL, ...)
## S3 method for class 'stepblock'
lines(x, type = "c", ...)
value 
a numeric vector containing the fitted values for each block; its length gives the number of blocks 
leftEnd 
a numeric vector of the same length as 
rightEnd 
a numeric vector of the same length as 
x0 
a single numeric giving the last unobserved sample point directly before sampling started, i.e. before 
x 
the object 
i , j , drop 
see 
type 

xlab , ylab , main , sub 
see 
... 
for generic methods only 
For stepblock
an object of class stepblock
, i.e. a data.frame
with columns value
, leftEnd
and rightEnd
and attr
ibute x0
.
For the purposes of this package step functions are taken to be leftcontinuous, i.e. the function jumps after the rightEnd
of a block.
However, step functions are usually sampled at a discrete set of points so that the exact position of the jump is unknown, except that it has to occur before the next sampling point; this is expressed in the implementation by the specification of a leftEnd
within the block so that every rightEnd
and leftEnd
is a sampling point (or the boundary of the observation window), there is no sampling point between one block's rightEnd
and the following block's leftEnd
, while the step function is constant at least on the closed interval with boundary leftEnd
, rightEnd
.
step
, stepfit
, family, [.data.frame
, plot
, lines
# step function consisting of 3 blocks: 1 on (0, 3]; 2 on (3, 6], 0 on (6, 8]
# sampled on the integers 1:10
f < stepblock(value = c(1, 2, 0), rightEnd = c(3, 6, 8))
f
# show different plot types
plot(f, type = "C")
lines(f, type = "E", lty = 2, col = "red")
lines(f, type = "B", lty = 3, col = "blue")
legend("bottomleft", legend = c("C", "E", "B"), lty = 1:3, col = c("black", "red", "blue"))