[Tutor] help with slice

[bob gailer]

bob gailer wrote:
> washakie wrote:
>   
>> Could someone please explain 'slices' also for dictionaries?
>>
>> basically, I'd like to know how you would call every 3rd element in a list
>> of lists... 
>>     
Call? Do you mean that these elements are callable objects (e.g. 
functions) which you want to "call", or are you just trying to get a 
list of the elements? My answer below addresses the 2nd meaning.

>> My logic says: ThirdElems=List[:][2]
>>
>> Which to me reads, for every item in List (which are lists), return the
>> third item.
>>   
>>     
> That is wishful reading. No basis in reality. List[:] gives you a 
> shallow copy of List. [2] then refers to the 3rd element of that copy.
>
> Try: [sublist[2] for sublist in List]
>
>   


-- 
Bob Gailer
919-636-4239 Chapel Hill, NC