seq {base} | R Documentation |
Generate regular sequences.
from:to seq(from, to) seq(from, to, by=) seq(from, to, length=) seq(along)
from |
starting value of sequence. |
to |
(maximal) end value of the sequence. |
by |
increment of the sequence. |
length |
desired length of the sequence. |
along |
take the length from the length of this argument. |
The interpretation of the unnamed arguments of seq
is
not standard, and it is recommended to always name the
arguments when programming.
The operator :
and the first seq(.)
form generate the
sequence from, from+1
, ..., to
.
seq
is a generic function.
The second form generates from, from+by
, ..., to
.
The third generates a sequence of length
equally spaced values
from from
to to
.
The last generates the sequence 1, 2
, ...,
length(along)
, unless the argument is of length 1 when it is
interpreted as a length
argument.
If from
and to
are factors of the same length, then
from : to
returns the ``cross'' of the two.
Very small sequences (with from - to
of the order of 1e-14
times the larger of the ends) will return from
.
The result is of mode
"integer"
if from
is
(numerically equal to an) integer and by
is not specified.
1:4 pi:6 # float 6:pi # integer seq(0,1, length=11) str(seq(rnorm(20))) seq(1,9, by = 2) # match seq(1,9, by = pi)# stay below seq(1,6, by = 3) seq(1.575, 5.125, by=0.05) seq(17) # same as 1:17 for (x in list(NULL, letters[1:6], list(1,pi))) cat("x=",deparse(x),"; seq(along = x):",seq(along = x),"\n") f1 <- gl(2,3); f1 f2 <- gl(3,2); f2 f1:f2 # a factor, the ``cross'' f1 x f2