On Mon, Jun 7, 2010 at 1:16 PM, Thomas Jollans wrote:
> On 06/07/2010 07:45 PM, Dan Stromberg wrote:
>
>
> Call me strange, but I regard this as a good place to use a functional
> style - IE, to use reduce, and furthermore I regard this as a good example
> of why reduce is useful for more than j
his loops through the list three times, which can be slow.
>
> I'd like to have something like this:
> count_a, count_b, count_c =
> sum( (int(x[1]=='a',int(x[1]=='b',int(x[1]=='c') for x in l)
>
> I hesitate
>
>> But this loops through the list three times, which can be slow.
>>
>> I'd like to have something like this:
>> count_a, count_b, count_c =
>> sum( (int(x[1]=='a',int(x[1]=='b',int(x[1]=='c') for x in l)
>>
>
ount_b, count_c =
sum( (int(x[1]=='a',int(x[1]=='b',int(x[1]=='c') for x in l)
I hesitate to use numpy array, because that will literally create and
destroy a ton of the arrays, and is likely to be slow.
If you want to do vector addition then numpy is the way to go
On Sat, Jun 5, 2010 at 6:20 PM, GZ wrote:
> Hi,
>
> I am looking for a fast internal vector representation so that
> (a1,b2,c1)+(a2,b2,c2)=(a1+a2,b1+b2,c1+c2).
>
> So I have a list
>
> l = ['a'a,'bb','ca','de'...]
>
> I want to count all items that start with an 'a', 'b', and 'c'.
>
> What I can d
Hi,
I am looking for a fast internal vector representation so that
(a1,b2,c1)+(a2,b2,c2)=(a1+a2,b1+b2,c1+c2).
So I have a list
l = ['a'a,'bb','ca','de'...]
I want to count all items that start with an 'a', 'b', and 'c'.
What I can do is:
count_a = sum(int(x[1]=='a') for x in l)
count_b = sum(
