Scan

Scan[f, expr] evaluates f applied to each element of expr in turn.

Scan[f, expr, levelspec] applies f to parts of expr specified by levelspec.

Scan[f, expr] discards the results of applying f to the subexpressions in expr. Unlike Map, Scan does not build up a new expression to return.

You can use Return to exit from Scan. Return[ret] causes the final value of Scan to be ret. If no explicit return values are specified, the final result from Scan is Null.

You can also use Throw to exit from Scan.

Scan is useful in carrying out an operation on parts of expressions where the operation has a "side effect", such as making an assignment.

Level specifications are described in Section A.3.6.

The default value for levelspec in Scan is {1}.

If expr is a SparseArray object, Scan[f, expr] applies f only to the values or subarrays that explicitly appear in expr.

See Section 2.2.4.

See also: Apply, Map, Level, Sow.

New in Version 1; modified in 3.

Further Examples