numericSequence class is a compact representation of a
numeric vector in an arithemetic sequence.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 is ignored, and a warning message is generated when the sequence is used.
If length is present and not 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) 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 fails if the input is not a regular arithmetic
sequence within a tolerance given by timeDateOptions("ts.eps").
Most operations on numericSequence objects (for example, mathematical functions,
arithmetic, comparison operators, or subscripting) work by first coercing to a numeric
vector, and therefore do not return numericSequence objects.
numericSequence function.