Re: [R] Recursive indexing failed at level 2

From: Duncan Murdoch <murdoch.duncan_at_gmail.com>
Date: Sat, 26 Jun 2010 09:07:58 -0400

Jim Hargreaves wrote:
> Hi Duncan, list,
>
> Thanks for the advice, but unfortunately that wasn't what was causing my
> problem. I'm still getting the "Recursive indexing failed at level 2"
> message even after replacing my unlist(pulse[i]) with pulse[[i]].
>

Read the second part of my first message, which explains the error. You had two errors in the original expression, and have only fixed one.

Duncan Murdoch
> Error:
>
> >
> pulse_subset[[1:as.numeric(length(pulse[[i]][as.numeric(peak_start[i]):as.numeric(peak_end[i])]))]]
> <- pulse[[i]][as.numeric(peak_start[i]):as.numeric(peak_end[i])]
> Error in
> pulse_subset[[1:as.numeric(length(pulse[[i]][as.numeric(peak_start[i]):as.numeric(peak_end[i])]))]]
> <- pulse[[i]][as.numeric(peak_start[i]):as.numeric(peak_end[i])] :
> recursive indexing failed at level 2
>
> It's almost as if the length of pulse[[i]] is too small, but it's length
> is 1001 and peak_start[i] and peak_end[i] are 192 and 208 respectively.
>
> Also why would the problem crop up only after 200,000 runs?
>
> Bizarre!
>
> Regards,
> Jim Hargreaves
>
>
>
> On 06/26/2010 01:38 PM, Duncan Murdoch wrote:
>
>> On 26/06/2010 8:29 AM, Jim Hargreaves wrote:
>>
>>> On 06/26/2010 01:20 PM, Duncan Murdoch wrote:
>>>
>>>> On 26/06/2010 7:53 AM, Jim Hargreaves wrote:
>>>>
>>>>> Dear fellow R users,
>>>>>
>>>>> I am replacing elements of a list like so:
>>>>>
>>>>> pulse_subset[[1:20]]=unlist(pulse[i])[1:20]
>>>>>
>>>> If pulse is a list, then pulse[i] is also a list, with one element.
>>>> I think you want pulse[[i]], which extracts element i.
>>>>
>>> Ahh, I specified pulse[i] has >20 values in my original mail.
>>>
>> But that could not be correct. Take a look at length(pulse[i]).
>> Assuming that i is a scalar value, length(pulse[i]) will be 1. You
>> really do want pulse[[i]]. You used unlist(pulse[i]) which is
>> sometimes the same as pulse[[i]], but it really depends on what
>> pulse[[i]] is. unlist() is a very crude tool, and you should avoid it
>> unless you really need it.
>>
>>
>>
>>> Basically pulse is a list 1000 elements long, with each element in
>>> pulse having between 1000 and 2000 elements of it's own. Pulse is a
>>> list of lists. Also as far as I am aware, [[ ]]'s should only be
>>> used when assigning values to elements of a list/vector.
>>>
>> Whoever told you that was mistaken.
>>
>> Duncan Murdoch
>>
>>> unlist(pulse[1]) gives x1, x2, x3, x4, x5 etc. etc.
>>>
>>>> If pulse_subset is a list, then pulse_subset[[1:20]] is equivalent
>>>> to pulse_subset[[1]][[2]][[3]][[4]] ... [[20]], i.e. the syntax
>>>> implies that it is a list containing a list etc, nested 20 levels
>>>> deep. The error message is telling you that it's not. I'm not sure
>>>> what your intention is in this case.
>>>> Duncan Murdoch
>>>>
>>>>> where pulse is a list of lists, and pulse [i] has >20 values.
>>>>>
>>>>> This gives the error "Recursive Indexing failed at level 2". But,
>>>>> interestingly this instruction is part of a loop which has gone
>>>>> through about 200,000 iterations before giving this error.
>>>>>
>>>>> Actual code:
>>>>>
>>>>> pulse_subset[[1:(length(unlist(pulse[i])[as.numeric(peak_start[i]):as.numeric(peak_end[i])]))]]
>>>>> <- unlist(pulse[i])[as.numeric(peak_start[i]):as.numeric(peak_end[i])]
>>>>>
>>>>> Error in
>>>>> pulse_subset[[1:(length(unlist(pulse[i])[as.numeric(peak_start[i]):as.numeric(peak_end[i])]))]]
>>>>> <-
>>>>> unlist(pulse[i])[as.numeric(peak_start[i]):as.numeric(peak_end[i])] :
>>>>> recursive indexing failed at level 2
>>>>>
>>>>> If anyone could shed some light I'd be rather grateful.
>>>>>
>>>>> Regards,
>>>>> Jim Hargreaves
>>>>>
>>>>> ______________________________________________
>>>>> R-help_at_r-project.org mailing list
>>>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>>>> PLEASE do read the posting guide
>>>>> http://www.R-project.org/posting-guide.html
>>>>> and provide commented, minimal, self-contained, reproducible code.
>>>>>
>>> ______________________________________________
>>> R-help_at_r-project.org mailing list
>>> https://stat.ethz.ch/mailman/listinfo/r-help
>>> PLEASE do read the posting guide
>>> http://www.R-project.org/posting-guide.html
>>> and provide commented, minimal, self-contained, reproducible code.
>>>
>
> ______________________________________________
> R-help_at_r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>



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https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code. Received on Sat 26 Jun 2010 - 13:11:08 GMT

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