length                 package:base                 R Documentation

Length of a Vector or List

Description:

     Get or set the length of vectors (including lists).

Usage:

     length(x)
     length(x) <- n

Arguments:

       x: a vector or list.

       n: an integer.

Details:

     The replacement form can be used to reset the length of a vector.
     If a vector is shortened, extra values are discarded and when a
     vector is lengthened, it is padded out to its new length with
     `NA's.

Value:

     The length of `x' as an `integer' of length 1, if `x' is (or can
     be coerced to) a vector or list.  Otherwise, `length' returns
     `NA'.

Examples:

     length(diag(4))# = 16 (4 x 4)
     length(options())# 12 or more
     length(y ~ x1 + x2 + x3)# 3
     length(expression(x, {y <- x^2; y+2}, x^y)) # 3

