append to the end of a dictionary

[Magnus Lycka]

Tim Chase wrote:
> I would lean towards using tuples, as in
> 
> ports = [('5631','udp'), ('5632', 'tcp'), ('3389','tcp'), ('5900','tcp')]
> 
> which you can then drop into your code:
> 
>     for (port, protocol) in ports:
>         print port, protocol
>         #do more stuff
> 
> This allows you to use the same port with both UDP and TCP.  If you want 
> to ensure that only one pair (port+protocol) can be in the list, you can 
> use a set() object:

But again, order will be lost (if that is of any consequence).

Another option would be to have a dict of sets keyed on port:

In Python 2.3:

 >>> import sets
 >>> ports = {}
 >>> def add_port(port, prot):
...     if port not in ports:
...         ports[port]=sets.Set()
...     ports[port].add(prot)
...
 >>> add_port(25, 'tcp')
 >>> add_port(25, 'udp')
 >>> add_port(80, 'tcp')
 >>> ports
{80: Set(['tcp']), 25: Set(['udp', 'tcp'])}
 >>> add_port(80, 'tcp')
 >>> ports
{80: Set(['tcp']), 25: Set(['udp', 'tcp'])}

Dicts have the obvious advantage that you can look up the protcols
used on a port without iterating over some sequence.