Sequence Generation

Description

The : and the first seq(.) form above generate the sequence from, from+1, ..., to. seq is a generic function.

The second, 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).

If from and to are factors of the same length, the “cross” of the two is returned.

Usage

from:to
seq(from, to)
seq(from, to, by=)
seq(from, to, length=)
seq(along)

Value

The result is of mode "integer" if from is (numerically equal to an) integer.

See Also

rep, sequence, row, col.

Examples

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)


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