Problem with List of List

[Fredrik Lundh]

Fredrik Lundh wrote:

>> I have a code
>> ==================CODE=============
>> List=[['1', 'a', '6'], ['1', 'b', '6'], ['1', 'c', '6'],
>>         ['1', 'd', '6'],['2', 'a','6'], ['2', 'b', '6'],
>>         ['2', 'c', '6'], ['2', 'd', '6'], ['3', 'a', '6'],
>>         ['3','b', '6'], ['4', 'a', '6'], ['4', 'b', '6']]
>>
>>
>> for x in List:
>>     temp=[]
>>     print x
>>     for y in List:
>>             if x[0]==y[0]:
>>                     print y[0],y[1]
>>                     temp.append(y)
>>     for z in temp:
>>            List.remove(z)
>>             print 'rem', z
> 
> the for loop uses an internal index to fetch items from the list you're 
> looping over, so if you remove items from it, you'll end up skipping 
> over items.

forgot to mention that the fix is to change the first for statement to:

     for x in List[:]:

</F>