array                  package:base                  R Documentation

_M_u_l_t_i-_w_a_y _A_r_r_a_y_s

_D_e_s_c_r_i_p_t_i_o_n:

     Creates or tests for arrays.

_U_s_a_g_e:

     array(data = NA, dim = length(data), dimnames = NULL)
     as.array(x)
     is.array(x)

_A_r_g_u_m_e_n_t_s:

    data: a vector (including a list) giving data to fill the array.

     dim: the dim attribute for the array to be created, that is a
          vector of length one or more giving the maximal indices in
          each dimension.

dimnames: the names for the dimensions. This is a list with one
          component for each dimension, either NULL or a character
          vector of the length given by 'dim' for that dimension.  The
          list can be names, and the names will be used as names for
          the dimensions.

       x: an R object.

_V_a_l_u_e:

     'array' returns an array with the extents specified in 'dim' and
     naming information in 'dimnames'.  The values in 'data' are taken
     to be those in the array with the leftmost subscript moving
     fastest.  If there are too few elements in 'data' to fill the
     array, then the elements in 'data' are recycled.  If 'data' has
     length zero, 'NA' of an appropriate type is used for atomic
     vectors ('0' for raw vectors) and 'NULL' for lists.

     'as.array()' coerces its argument to be an array by attaching a
     'dim' attribute to it.  It also attaches 'dimnames' if 'x' has
     'names'. The sole purpose of this is to make it possible to access
     the 'dim'[names] attribute at a later time.

     'is.array' returns 'TRUE' or 'FALSE' depending on whether its
     argument is an array (i.e., has a 'dim' attribute of positive
     length) or not.  It is generic: you can write methods to handle
     specific classes of objects, see InternalMethods.

_R_e_f_e_r_e_n_c_e_s:

     Becker, R. A., Chambers, J. M. and Wilks, A. R. (1988) _The New S
     Language_. Wadsworth & Brooks/Cole.

_S_e_e _A_l_s_o:

     'aperm', 'matrix', 'dim', 'dimnames'.

_E_x_a_m_p_l_e_s:

     dim(as.array(letters))
     array(1:3, c(2,4)) # recycle 1:3 "2 2/3 times"
     #     [,1] [,2] [,3] [,4]
     #[1,]    1    3    2    1
     #[2,]    2    1    3    2

