Generalized padding for arrays of arbitrary dimension
Usage
apad(a, l, e = NULL, method = "ext", post = TRUE)
Arguments
a
Array to be padded
l
Amount of padding to add. If a vector of length greater than
one, it is interpreted as
the extra extent of a along each of its dimensions (standard
recycling is used). If of length one, interpret as the dimension to be
padded, in which case the amount is given by argument l.
e
If l is of length one, the amount of padding to add to
dimension l
method
String specifying the values of the padded elements. See
details section.
post
Boolean, with default TRUE meaning to append to
a and FALSE meaning to prepend.
Details
Argument method specifies the values of the padded elements.
It can be either “ext”,
“mirror”, or “rep”.
Specifying ext (the default) uses a padding value given by
the “nearest” element of a, as measured by the
Manhattan metric.
Specifying mirror fills the array with alternate mirror
images of a; while rep fills it with unreflected copies
of a.
# NOT RUN {apad(1:10,4,method="mirror")
a <- matrix(1:30,5,6)
apad(a,c(4,4))
apad(a,c(4,4),post=FALSE)
apad(a,1,5)
apad(a,c(5,6),method="mirror")
apad(a,c(5,6),method="mirror",post=FALSE)
# }