[R] Subsetting a list of lists using lapply

[Aron Lindberg]

Hmm…Chuck’s solution may actually be problematic because there are several entries which at the deepest level are called “sha”, but that should not be included, such as:





input[[67]]$content[[1]]$commit$tree$sha




and




input[[67]]$content[[1]]$parents[[1]]$sha





it’s only the “sha” that fit the following subsetting pattern that should be included:





input[[i]]$content[[1]]$sha[1]




It’s getting thornier!




To be fair to Rolf’s solution (which probably can be updated to solve the problem), I’ve posted the complete dput here:

https://gist.githubusercontent.com/aronlindberg/92700c04c88ff112e4f7/raw/0f3cd8468f4dc82267be3cec72d53a7a04f5c449/dput.R







-- 

Aron Lindberg




Doctoral Candidate, Information Systems

Weatherhead School of Management 

Case Western Reserve University

aronlindberg.github.io

On Fri, Feb 20, 2015 at 8:25 AM, Aron Lindberg <aron.lindberg at case.edu>
wrote:

> Thanks Chuck and Rolf.
> While Rolf’s code also works on the dput that I actually gave you (a smaller subset of the full dataset), it failed to work on the larger dataset, because there are further exceptions:
> input[[i]]$content[[1]] is sometimes a list, sometimes a character vector, and sometimes input[[i]]$content simply returns list().
> Chuck’s solution however bypasses this and works on the full dataset (which was 8mb, which is why I didn’t upload it as a gist).
> Best,
> Aron
> -- 
> Aron Lindberg
> Doctoral Candidate, Information Systems
> Weatherhead School of Management 
> Case Western Reserve University
> aronlindberg.github.io
> On Fri, Feb 20, 2015 at 12:44 AM, Charles Berry <ccberry at ucsd.edu> wrote:
>> Aron Lindberg <aron.lindberg <at> case.edu> writes:
>>> 
>>> Hi Everyone,
>>> 
>>> I'm working on a thorny subsetting problem involving list of lists. I've put a 
>> dput of the data here:
>>> 
>>> 	https://gist.githubusercontent.com/aronlindberg/b916dee897d051ac5be5/
>> raw/a78cbf873a7e865c3173f943ff6309ea688c653b/dput
>>> 
>> IIUC, you want the value of every list element that is named "sha" and 
>> that name will only apply to atomic objects.
>> If so, this should do it. 
>>> input <- dget("/tmp/dpt")
>>> shas <- unlist( input, use.names=FALSE )[ grepl( "sha", names(unlist(input)))]
>>> input[[67]]$content[[1]]$sha
>> [1] "58cf43ecdc1beb7e1043e9de612ecc817b090f15"
>>> which(input[[67]]$content[[1]]$sha == shas )
>> [1] 194
>> HTH,
>> Chuck
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