Colon {base}  R Documentation 
Colon Operator
Description
Generate regular sequences.
Usage
from:to
a:b
Arguments
from 
starting value of sequence. 
to 
(maximal) end value of the sequence. 
a , b 

Details
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 other 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 1e7
.
Nonnumeric arguments are coerced internally (hence without
dispatching methods) to numeric—complex values will have their
imaginary parts discarded with a warning.
Value
For numeric arguments, a numeric vector. This will be of type
integer
if from
is integervalued and the result
is representable in the R integer type, otherwise of type
"double"
(aka mode
"numeric"
).
For factors, an unordered factor with levels labelled as la:lb
and ordered lexicographically (that is, lb
varies fastest).
References
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.)
See Also
seq
(a generalization of from:to
).
As an alternative to using :
for factors, interaction
.
For :
used in the formal representation of an interaction, see
formula
.
Examples
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