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you get duplicate values, because there are duplicateed probe IDs on
the
array.
Each probe set contains 16(11)-25 different values. This probes are
equally
distributed on the array to ascertain an equal distribution of the
signal
for all probe IDs.
you can use the aggregate command to calculate the median (or for that
point any function you would like to apply to the values.) of the
different
expression values
Use something like that:
median_rawData <- aggregate(rawData[,"columns is the data in"],
list("Probe
ID to merge"), FUNCTION)
For the analysis of the arrays, you don't have to create a separate
expressionSet object. It will be created automatically, if you
normalize
the data with e.g. rma or gcrma. Just follow one of the tutorials on
the
web or in bioconductor. They are quite easy to understand and will do
everything for the beginning of the analysis.
Hope this help a bit more
Assa
On Mon, Jan 6, 2014 at 11:57 AM, shweta bagewadi
<bagewadi.shweta@gmail.com>wrote:
> Hi Assa,
>
> here is what I want to do:
>
> - get the raw intensities values (as exprs object) of affybatch
object
> (reading from the raw data direxctly), along with the probe IDS
> - get the normalized intesity values of the affybatch object
> - Compare the intesities between the two generated results by
looking at
> the probe intensity values
>
> The code you sent me produced duplicate probe values, see below:
>
> affyIDs AFX_1_A1.CEL AFX_1_A2.CEL AFX_1_A3.CEL
AFX_1_A4.CEL
> 369707 1007_s_at 200 201 208
202
> 563318 1007_s_at 398 491 425
464
> 1049349 1007_s_at 427 547 528
446
>
>
> I already tried something simple:
>
> data<-ReadyAffy()
> expr <- exprs(data)
> eset <- new("ExpressionSet", exprs = expr, phenoData = pheno)
>
> Still the probe IDS are missing for the eset object.
>
>
> Can anyone help me on how to extract raw intensity values from an
affy
> object.
>
> regards,
> Shweta
> ---------- Forwarded message ----------
> From: Assa Yeroslaviz <frymor@gmail.com>
> Date: Mon, Jan 6, 2014 at 11:42 AM
> Subject: Re: Help needed: extracting raw intensity values from Affy
> To: shweta bagewadi <bagewadi.shweta@gmail.com>
>
>
> Hi,
>
> here is something I did for my arrays.
> It depends what kind of arrays you are using.
>
> Data<-ReadAffy(celfile.path="path to your arrrays" ,filenames="Name
of
> files" phenoData="Phenodata", verbose=TRUE)
> mypm <- pm(Data) # Retrieves PM intensity values for single probes
> mymm <- mm(Data) # Retrieves MM intensity values for single probes
> affyIDs <- probeNames(Data) # Retrieves Affy IDs
> result <- data.frame(affyIDs, mypm, mymm) # Combines the above
information
> in data frame
>
>
> Hope this is helping
>
> cu,
> Assa
>
> PS.
>
> please write to the forum (put the person than on cc), as I am sure
you'll
> will get help much faster.
>
>
>
> On Mon, Jan 6, 2014 at 10:35 AM, shweta bagewadi <
> bagewadi.shweta@gmail.com> wrote:
>
>> Hi,
>>
>> I saw in BioC blog that u have created a thread on hopw to extract
raw
>> intensity values from affy object. I am also trying to do the same.
>> Unfortunately, I do not see any solution in this thread.
>>
>> Did you find a solution for it? If yes, could you please guide me
how you
>> did it.
>>
>> Thanlks in advance.
>>
>> --
>> Regards,
>> Shweta
>>
>
>
>
>
> --
> Regards,
> Shweta
>
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