Re: [R] problem with for()

From: Simone Gabbriellini <ogabbrie_at_tin.it>
Date: Thu 04 Aug 2005 - 18:18:49 EST

Marc,
I did it with the simple trick of keepin separate vector values and index values, as you suggested in your mail

it was simple, but you know, it's always simple when you've done it :)

thank you very much,
simone

Il giorno 04/ago/05, alle ore 00:39, Marc Schwartz ha scritto:

> It would help to have an example of what it is you are trying to do.
>
> Importantly, keep separate the need to have zero be a value in a
> vector
> as opposed to using zero to index a vector.
>
> As I note below in my reply, you can have:
>
>
>> x <- 0:5
>>
>
>
>> x
>>
> [1] 0 1 2 3 4 5
>
>
>> x ^ 2
>>
> [1] 0 1 4 9 16 25
>
> Marc
>
> On Thu, 2005-08-04 at 00:25 +0200, Simone Gabbriellini wrote:
>
>> how can I have a 0 evaluated in my loop then?
>> it is important for my algorithm
>>
>> do you have any hints?
>>
>> simone
>>
>> Il giorno 03/ago/05, alle ore 23:37, Marc Schwartz ha scritto:
>>
>>
>>> On Wed, 2005-08-03 at 23:24 +0200, Simone Gabbriellini wrote:
>>>
>>>
>>>> Dear list,
>>>> can someone tell me why this two pieces of code give me the same
>>>> results?
>>>>
>>>>
>>>>
>>>>> for(i in 0:5){ sum[i] = i }
>>>>> sum
>>>>>
>>>>>
>>>> [1] 1 2 3 4 5
>>>>
>>>>
>>>>
>>>>> for(i in 1:5){ sum[i] = i }
>>>>> sum
>>>>>
>>>>>
>>>> [1] 1 2 3 4 5
>>>>
>>>> shouldn't the first one be
>>>>
>>>> 0 1 2 3 4 5
>>>>
>>>> thank you,
>>>> simone
>>>>
>>>>
>>>
>>> No....the indexing of R objects is 1 based. Thus your first loop
>>> tried
>>> to set i[0], which is a non-existent entry.
>>>
>>>
>>>
>>>> i <- 0:5
>>>>
>>>>
>>>
>>>
>>>
>>>> i
>>>>
>>>>
>>> [1] 0 1 2 3 4 5
>>>
>>>
>>>
>>>> i[0]
>>>>
>>>>
>>> numeric(0)
>>>
>>>
>>>
>>>> i[1]
>>>>
>>>>
>>> [1] 0
>>>
>>> HTH,
>>>
>>> Marc Schwartz
>>>
>>>
>>>
>>>
>>>
>
>



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