| Colon {base} | R Documentation |
Generate regular sequences.
from:to a:b
from |
starting value of sequence. |
to |
(maximal) end value of the sequence. |
a, b |
factors of same length. |
The binary operator : has two meanings: for factors a:b is
equivalent to interaction(a, b) (but the levels are
ordered and labelled differently).
For numeric arguments from:to is equivalent to seq(from, to),
and generates a sequence from from to to in steps of 1
or 1-. Value to will be included if it differs from
from by an integer up to a numeric fuzz of about 1e-7.
For numeric arguments, a numeric vector. This will be of type
integer if from and to are both integers
and representable in the integer type, otherwise of type
numeric.
For factors, an unordered factor with levels labelled as la:lb
and ordered lexicographically (that is, lb varies fastest).
Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988)
The New S Language.
Wadsworth & Brooks/Cole.
(for numeric arguments: S does not have : for factors.)
seq.
As an alternative to using : for factors, interaction.
For : used in the formal representation of an interaction, see
formula.
1:4 pi:6 # real 6:pi # integer f1 <- gl(2,3); f1 f2 <- gl(3,2); f2 f1:f2 # a factor, the "cross" f1 x f2