# 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

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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