Re: Exception Names

Tom Anderson wrote:


     Ugh. Out of curiosity, how does a Python programmer manage
multiple "parallel" iterations? For example, let's suppose I
want to print a two-column list of the children in a kindergarten
class, the boys in one column and the girls in the other. In
Java, I might write

    List<Child> boys = ...;
    List<Child> girls = ...;
    Iterator<Child> ib = boys.iterator();
    Iterator<Child> ig = girls.iterator();
    while (ib.hasNext() || ig.hasNext()) {
        if (ib.hasNext())
            System.out.print(ib.next());
        if (ig.hasNext()) {
            System.out.print("\t"); // crude, but just for example
            System.out.print(ig.next());
        }
        System.out.println();
    }

Lacking hasNext(), how does the Python programmer proceed? The Java
solution that comes to mind is to write a helper method

    static Child getNext(Iterator<Child> it) {
        try {
            return it.next();
        }
        catch (NoSuchElementException ex) {
            return null;
        }
    }

.... and use comparisons against null instead of the hasNext() tests.
But this is really just re-implementing hasNext() on the sly! Does
Python offer something better?

--
Eric.Sosman@sun.com