2009/3/29 baptiste auguie <ba208@exeter.ac.uk>

> Hi,
> Thanks Dott. baptiste,


but I wish not the Sum of element but count the numeber of element and
obtain a new data.frame.  Like your data.frame: myData

library(library(plyr)

# create a data.frame
myData <- data.frame(ID=rep(c(1:4),each=4),
count=abs(ceiling(rnorm(16,8,4))))
#count the number of sample in each ID area
count_myData <- ddply(myData, .(ID), transform, sum = sum(count >=0, na.rm =
T))


ID count sum
1   1     0   4
2   1     9   4
3   1    11   4
4   1    16   4
5   2     9   4
6   2     8   4
7   2    11   4
8   2    10   4
9   3    16   4
10  3     1   4
11  3     0   4
12  3     8   4
13  4     8   4
14  4    10   4
15  4    11   4
16  4     5   4

now I searching to create a new DF like this:

 ID count
1  4
2   4
3   4
4   4
 Thanks
Gianni


> could you provide an example for the data in "sample"?  (incidentally, note
> that sample is already the name of a built-in function)
>
> I'm guessing you could do something like,
>
>
>> library(doBy)
>> summaryBy(count~ID, data= count_myData, FUN=sum)
>>
>
> tested with,
>
> count_myData <- data.frame(ID=rep(c(1:4),each=4),
> count=abs(ceiling(rnorm(16,8,4))))
>
>
> hope this helps,
>
> baptiste
>
>
> On 29 Mar 2009, at 17:54, gianni lavaredo wrote:
>
>   Dear R user,
>>
>> Thanks for this sunday attention about my problem. I have a data.frame
>> like
>> this example:
>>
>> count_myData
>>
>> ID: 1,1,1,1,2,2,2,3,3,3,3,3,4,4,4,4,4,4
>> count: 4,4,4,4,3,3,3,5,5,5,5,5,6,6,6,6,6,6
>>
>> this data.frame derived from this code
>>
>> count_myData <- ddply(sample, .(ID), transform, sum = sum(Z >=0, na.rm =
>> T))
>>
>> with this I have the number of sample inside of area with ID 1, ID 2 ID 3
>> etc etc.
>> Now I need a data.frame like this
>>
>> new_myData
>> ID:1,2,3,4
>> count:4,3,5,6
>>
>> Thanks Gianni
>>
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>>
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>
> _____________________________
>
> Baptiste Auguié
>
> School of Physics
> University of Exeter
> Stocker Road,
> Exeter, Devon,
> EX4 4QL, UK
>
> Phone: +44 1392 264187
>
> http://newton.ex.ac.uk/research/emag
> ______________________________
>
>

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