[Tutor] all elements equal in tuple or list

[Kent Johnson]

Bob Gailer wrote:
> At 08:06 AM 11/18/2004, Kent Johnson wrote:
>> def test(vals):
>>     if not vals: return True
>>
>>     i = iter(vals)
>>     first = i.next()
>>     for item in i:
>>         if first != item:
>>             return False
>>     return True
>>
>> vals1 = [1, 1, 1, 1]
>> vals2 = [1, 2, 1, 1]
>> vals3 = [2, 1, 1, 1]
>>
>> print test(vals1)
>> print test(vals2)
>> print test(vals3)
> 
> 
> Would not the following be a bit simpler?
> def test(vals):
>     if vals:
>         for item in vals[1:]:
>             if vals[0] != item:
>                return False
>     return True

A little shorter, but it has to copy vals[1:] and it deferences vals[0] 
each time through the loop.

You could write mine as

def test(vals):
     if vals:
         i = iter(vals)
         first = i.next()
         for item in i:
             if first != item:
                 return False
     return True

and yours as

def test(vals):
     if vals:
	first = vals[0]
         for item in vals[1:]:
             if first != item:
                return False
     return True

which shows that they are very similar.

For short lists, I doubt it makes much difference which one you use. For 
longer lists, I expect mine would have an edge but I haven't tested that 
assumption!

Kent

> 
> Bob Gailer
> bgailer at alum.rpi.edu
> 303 442 2625 home
> 720 938 2625 cell
>