[R] A question about "union"

[Leon Yee]

But the problem is that I have MANY vectors, whose names are of some 
specific pattern. It is not good for us to write a very long expression.

vectors <- list(ls(pattern="xyz"))  didn't get what I want.

Leon

Wacek Kusnierczyk wrote:
> ... but it seems to me a better solution to have the vectors you need in
> a list, and then iterate over the list, rather than have to look the
> vectors up by name:
> 
> vectors = list(v1, v2, 1:10, ...)
> u = NULL
> for (v in vectors) u = union(u, v)
> 
> when you use get, you start to explicitly play with environments, and
> you should be knowing what you do, otherwise ugly surprizes await.
> 
> vQ
> 
> 
> Leon Yee wrote:
>> Cool! It works!
>>
>> Thank you very much!
>>
>> Leon
>>
>> Yihui Xie wrote:
>>> You need to get() their elements instead of merely using variable names.
>>>
>>> Regards,
>>> Yihui
>>> -- 
>>> Yihui Xie <xieyihui at gmail.com>
>>> Phone: +86-(0)10-82509086 Fax: +86-(0)10-82509086
>>> Mobile: +86-15810805877
>>> Homepage: http://www.yihui.name
>>> School of Statistics, Room 1037, Mingde Main Building,
>>> Renmin University of China, Beijing, 100872, China
>>>
>>>
>>>
>>> On Fri, Oct 17, 2008 at 6:23 PM, Leon Yee <yee.leon at gmail.com> wrote:
>>>> Dear all,
>>>>
>>>>   I have a question about "union".  "union" handles two vectors'
>>>> elements to
>>>> get their union, but I have many vectors and I want to get the union
>>>> of all
>>>> of them. So I wrote a loop:
>>>>
>>>> all <-c();
>>>> for(var in ls(pattern="xyz"))
>>>> # all of the vectors with pattern of "xyz"
>>>> {
>>>>   all <- union(all, var);
>>>> }
>>>>
>>>>
>>>> but the result is like this: ("xyzblabla1", "xyzblabla2", "abcxyz",
>>>> ... ) --
>>>> just a collection of the variable names, not the union of their
>>>> elements.
>>>>
>>>> How can I solve this problem?
>>>>
>>>> thanks!
>>>>
>>>> Leon
>>>>
>>>> ______________________________________________
>>>> 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.
> 
>