Christoph Zwerschke wrote:
> The example above is a bit misleading, because using 'a', 'b' as keys
> can give the impression that you just have to sort() the keys to have
> what you want. So let's make it more realistic:
>
> d = { 'pid': ('Employee ID', 'int'),
> 'name': ('Employee name', 'varchar'),
> 'sal': ('Salary', 'float') }
>
> Now if I want these things to be presented in this order, I need to run
> through a separate list ('pid', 'name', 'sal') that holds the order.
>
> Ok, you could simply use a list instead of a dictionary:
>
> d = ( ('pid', 'Employee ID', 'int'),
> ('name', 'Employee name', 'varchar'),
> ('sal', 'Salary', 'float') )
if you restructure the list somewhat
d = (
('pid', ('Employee ID', 'int')),
('name', ('Employee name', 'varchar')),
('sal', ('Salary', 'float'))
)
you can still loop over the list
for key, (name, type) in d:
print key, name, type # e.g. generate form entry
> This works as long as you *only* have to go through the list
> sequentially. But maybe you want to print the name with its description
> at some other place as well. Now how do you access its description
> 'Employee name' so easily?
but you can easily generate an index when you need it:
index = dict(d)
name, type = index["pid"]
print name
the index should take less than a microsecond to create, and since it
points to the members of the original dict, it doesn't use much memory
either...
</F>
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