aggregate isn't really what I want. Maybe tapply? I still can't get
it to work.
> length(mylist)
[1] 4
> length(names)
[1] 4
> tapply(mylist, names, merge)
Error in tapply(mylist, names, merge) : arguments must have same length
I guess because a list isn't an atomic data type. What function will
do the same on lists? lapply doesn't have a 'by' argument.
On Fri, Jun 3, 2016 at 1:41 PM, Ed Siefker <ebs15...@gmail.com> wrote:
> I manually constructed the list of sample names and tried the
> aggregate call I mentioned.
> Merge works when called manually, but not when using aggregate.
>
>> mylist <- list(data.frame(name="sample1", red=20),
>> data.frame(name="sample1", green=15), data.frame(name="sample2", red=10),
>> data.frame(na me="sample2", green=30))
>> names <- list("sample1", "sample1", "sample2", "sample2")
>> merge(mylist[1], mylist[2])
> name red green
> 1 sample1 20 15
>> merge(mylist[3], mylist[4])
> name red green
> 1 sample2 10 30
>> aggregate(mylist, by=as.list(names), merge)
> Error in as.data.frame(y) : argument "y" is missing, with no default
>
> What's the right way to do this?
>
> On Fri, Jun 3, 2016 at 1:20 PM, Ed Siefker <ebs15...@gmail.com> wrote:
>> I have a list of data as follows.
>>
>>> list(data.frame(name="sample1", red=20), data.frame(name="sample1",
>>> green=15), data.frame(name="sample2", red=10), data.frame(name="sample 2",
>>> green=30))
>> [[1]]
>> name red
>> 1 sample1 20
>>
>> [[2]]
>> name green
>> 1 sample1 15
>>
>> [[3]]
>> name red
>> 1 sample2 10
>>
>> [[4]]
>> name green
>> 1 sample2 30
>>
>>
>> I would like to massage this into a data frame like this:
>>
>> name red green
>> 1 sample1 20 15
>> 2 sample2 10 30
>>
>>
>> I'm imagining I can use aggregate(mylist, by=samplenames, merge)
>> right? But how do I get the list of samplenames? How do I subset
>> each dataframe inside the list?
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