numericSequence
class is a compact representation of a
numeric vector in an arithemetic sequence.
numeric
) the start of the sequence.
numeric
) the end of the sequence.
numeric
) the increment for the sequence.
integer
) the length of the sequence.
The
numericSequence
class extends the
positionsNumeric
class.
Valid
numericSequence
objects must contain a single non-
NA
number in
at least three of the four slots. If all four are present, the
length
slot will be ignored, and a warning message will be generated when
the sequence is used. If
length
is present and not being ignored, it must
be non-negative [a zero-length sequence is equivalent to
numeric(0)
].
Otherwise, the sign of the
by
slot must agree with the sign of
(to - from)
in order to have a valid sequence;
in particular, if
by
is zero then
to
and
from
must be equal. The
default sequence [generated by calling
numericSequence()
or
new("numericSequence")
] has length 0.
A
numericSequence
can be coerced to
numeric
or
integer
using
as
,
and regularly spaced numbers can be coerced to
numericSequence
using
as
, [this will fail if the input is not a regular arithmetic
sequence within a tolerance given by
options("ts.eps")
]. Most
operations on
numericSequence
objects (e.g. mathematical functions,
arithmetic,
comparison operators, subscripting) work by first coercing to a numeric
vector, and therefore do not return
numericSequence
objects.