Newbie Q on searching lists

[Sean 'Shaleh' Perry]

On Friday 22 November 2002 21:45, Kenny Tilton wrote:
> I see the index method on lists throws an error if the element sought is
> not found. I was hoping it would return None.
>
> The semantics I am coding happen to throw an error if a certain element
> is found in a list, so i want to code:
>
>     if calculators.index[thisCalculator]:
>        raise CircularDependency, thisCalculator
>
> 1. Am I missing something?
>

if calculators.count(thisCalculator): # returns zero if not found
   raise CircularDependency, thisCalculator

print count.__doc__
count(value) -> integer -- return number of occurrences of value

> 2. Can I add a method to List that has the behavior I am after?
>

in the new python 2.2 code base you can derive from list and add a new method

> 3. Should I just start a module of my favorite utilities and create there:
>
> def find( item, list):
>    try: yada yada...
>

not always a bad option either