Allows access to matrices or strings in memory from inside a data loop.
This example shows how to assign the contents of an external vector to
a new variable in the dataset, by iteratively assigning a range of
elements to the variable. The reserved variable
x_x contains the data
read from the input dataset on each iteration. The external vector
must have at least as many rows as the dataset.
/* ** Used to index a range of ** elements from exvec */ base = 1; dataloop oldata newdata; extern base, exvec; make ndvar = exvec[seqa(base, 1, rows(x_x))]; /* ** Execute command ** literally */ # base = base + rows(x_x); endata;
Commas in variable_list are optional.
extern statement tells the translator not to generate local code for the listed
variables, and not to assume that they are elements of the input data
extern statements should be placed before any reference to the symbols
listed. The specified names should not exist in the input dataset, or
be used in a