# [R] Sorting

David Neu david at davidneu.com
Sat Feb 6 21:43:20 CET 2010

```Hi Don,

> Which one is larger, mylist\$v1 or mylist\$v2? Longer, yes, mylist\$v2 is
> longer. But larger?
Sure, given any two vectors the goal is to be able to use any criteria
to determine if the first vector is "larger than" the second one.  The
key requirement is that depending on the criteria I may need both
vectors in hand to perform the test.

Cheers,
David

On Sat, Feb 6, 2010 at 3:00 PM, Don MacQueen <macq at llnl.gov> wrote:
> I have trouble making sense of the question, and I wonder if there is a
> terminology issue.
>
> For example, you have a list like this one:
>
>  mylist <- list( v1=1:3, v2=1:4, v3=1:5, v4=1:6)
>
> (That is, a list of vectors of varying lengths.)
>
> You want to apply a function to each pair of vectors:
>  First to v1 and v2,
>  Then to v2 and v3,
>  Then to v3 and v4
> ?
> And also to pairs v1 and v3, v1 and v4, and so on?
>
> Which one is larger, mylist\$v1 or mylist\$v2? Longer, yes, mylist\$v2 is
> longer. But larger?
>
> And ultimately you want to have the list with its elements in some other
> order,
> perhaps v4 comes first, then v3, and so on?
>
> -Don
>
>
> At 1:21 PM -0500 2/6/10, David Neu wrote:
>>
>> Hi,
>>
>> I have a list of vectors (of varying lengths).  I'd like to sort this
>> list by applying a function to each pair of vectors in the list and
>> returning information to sorting routine that let's it know which one
>> is larger.
>>
>> To solve problems like this in Common Lisp, the sort function accepts
>> a function as an argument.  The arguments to this function are two
>> elements of the list which is being sorted.  The writer of the
>> function returns t (TRUE in R) when the first argument to the function
>> is larger than the second and nil (FALSE in R) otherwise.
>>
>> I'm wondering if there is some way to accomplish this in R.
>>
>> Many thanks for any help!
>>
>> Cheers,
>> David
>>
>> ______________________________________________
>> R-help at r-project.org mailing list
>> https://*stat.ethz.ch/mailman/listinfo/r-help
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>> and provide commented, minimal, self-contained, reproducible code.
>
>
> --
> --------------------------------------
> Don MacQueen
> Environmental Protection Department
> Lawrence Livermore National Laboratory
> Livermore, CA, USA
> 925-423-1062
> --------------------------------------
>

```