Building lists

Seymore4Head Seymore4Head at Hotmail.invalid
Mon Oct 20 23:57:17 CEST 2014


On Tue, 21 Oct 2014 10:54:55 +1300, Gregory Ewing
<greg.ewing at canterbury.ac.nz> wrote:

>Seymore4Head wrote:
>> Say I want a
>> Grocery list and it will have a maximum size of 50 items.
>
>In Python it's actually easier to deal with variable-sized
>lists having no maximum size. Instead of pre-creating a list
>of a given size, just start with an empty list and append
>things to it.
>
>Unless there's some external reason for a size limit (e.g.
>you can't fit more than 50 items in your shopping bag)
>there's no need to impose limit at all. You should
>certainly start without a limit and only add it later
>if needed.
>
>Some things to get you started:
>
>items = [] # Start with an empty list
>items.append("cheese") # Add some items to it
>items.append("eggs")
>items.append("milk")
>for item in items: # Process the items
>     print(item)
>
>If you really need to limit the number of items, you
>can do something like this:
>
>def add_item(item):
>     if len(items) < 50:
>         items.append(item)
>     else:
>         raise Exception("Shopping list is full")

Thanks.



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