Thanks for the great helps from David, Jim and Liviu. It solved my problem.

Appreciated!

On Thu, Sep 1, 2011 at 11:01 AM, David Winsemius <dwinsemius@comcast.net>wrote:

>
> On Sep 1, 2011, at 1:53 PM, Changbin Du wrote:
>
>  HI, Dear R community,
>>
>> I want to split a data frame by using two variables: let and g
>>
>>  x = data.frame(num =
>>>
>> c(10,11,12,43,23,14,52,52,12,**23,21,23,32,31,24,45,56,56,76,**45), let =
>> letters[1:5], g = 1:2)
>>
>>> x
>>>
>>  num let g
>> 1   10   a 1
>> 2   11   b 2
>> 3   12   c 1
>> 4   43   d 2
>> 5   23   e 1
>> 6   14   a 2
>> 7   52   b 1
>> 8   52   c 2
>> 9   12   d 1
>> 10  23   e 2
>> 11  21   a 1
>> 12  23   b 2
>> 13  32   c 1
>> 14  31   d 2
>> 15  24   e 1
>> 16  45   a 2
>> 17  56   b 1
>> 18  56   c 2
>> 19  76   d 1
>> 20  45   e 2
>>
>> I tried the following:
>>
>> xs = split(x,x$g*x$let)
>>
>
> Probably
>
>  xs = split(x,list(x$g,x$let))
>
>>
>> *Warning message:
>> In Ops.factor(x$g, x$let) : * not meaningful for factors*
>>
>>
>> xs = split(x,c(x$g*x$let))
>>
>> *Warning message:
>> In Ops.factor(x$g, x$let) : * not meaningful for factors
>> *
>>
>> Can someone give some hints?
>>
>> Thanks!
>>
>>
>> --
>> Sincerely,
>> Changbin
>> --
>>
>>        [[alternative HTML version deleted]]
>>
>> ______________________________**________________
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>> PLEASE do read the posting guide http://www.R-project.org/**
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>> and provide commented, minimal, self-contained, reproducible code.
>>
>
> David Winsemius, MD
> West Hartford, CT
>
>


-- 
Sincerely,
Changbin
--

Changbin Du
Data Analysis Group, Affymetrix Inc
6550 Emeryville, CA, 94608

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