Paddy kirjoitti:
> On Feb 25, 2:01 am, [EMAIL PROTECTED] wrote:
>> While working with lists of tuples is probably very common, none of my
>> five Python books or a Google search tell me how to refer to specific items
>> in each tuple. I find references to sorting a list of tuples, but not
>> extracting tuples based on their content.
>>
>> In my case, I have a list of 9 tuples. Each tuple has 30 items. The first
>> two items are 3-character strings, the remaining 28 itmes are floats.
>>
>> I want to create a new list from each tuple. But, I want the selection of
>> tuples, and their assignment to the new list, to be based on the values of
>> the first two items in each tuple.
>>
>> If I try, for example, writing:
>>
>> for item in mainlist:
>> if mainlist[item][0] == 'eco' and mainlist[item][1] == 'con':
>> ec.Append(mainlist[item][2:])
>>
>> python doesn't like a non-numeric index.
>>
>> I would really appreciate a pointer so I can learn how to manipulate lists
>> of tuples by referencing specific items in each tuple (string or float).
>>
>> Rich
>
> You might also use list comprehensions to accumulate the values you
> need:
>
> ec = [ item[2:] for item in mainlist if item[:2] == ['eco','con'] ]
>
> - Paddy.
>
I'm nitpicking, but the OP has a list of tuples:
ec = [ item[2:] for item in mainlist if item[:2] == ('eco','con') ]
Cheers,
Jussi
--
http://mail.python.org/mailman/listinfo/python-list
