R help - Apr 2012 - How insert data to a column in existing csv file?

I was working with some excel files with a lot of data. 
And by hand it is impossible to handle them. 
So they are now converted to .csv. 

With headers above the columns, like:  
Data1, Data2, Data3 

But now I needed to calculate the log2 value of Data1 and place the result
under Data2. 
I can't find how to do that. 
Does anyone else know? 

I have the log2 values, but how do I get then inside the .csv file under
Data2? 

I already tried write.table(), buy that wasn't it. 
And I am kinda stuck on this now..... 


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Hi,
You can use write.table with Append = TRUE to keep on writing in the same
csv file, but I don't know how to write in an specific cell of your csv
file. 
 http://stat.ethz.ch/R-manual/R-devel/library/utils/html/write.table.html

write.table (data, file = "example.csv", sep = ";",
col.names = NA, append TRUE, dec =",")

I think the best thing to do once you have imported your data into R is to
create a new csv file and write in it the table you need.

Hope it helps, R

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On Apr 12, 2012, at 5:18 AM, Yellow wrote:
> I was working with some excel files with a lot of data.
> And by hand it is impossible to handle them.
> So they are now converted to .csv.
>
> With headers above the columns, like:
> Data1, Data2, Data3
>
> But now I needed to calculate the log2 value of Data1 and place the  
> result
> under Data2.
> I can't find how to do that.
First you need to explain more clearly what you mean by "place the  
result
under Data2". Is this a display concern? Or are you trying to  
interleave rows of original data and logged data using a column  
organization? Why only Data2? What should go in the rows for Data1 and  
Data3? ? What is the goal of this effort?

> Does anyone else know?
>
> I have the log2 values, but how do I get then inside the .csv file  
> under
> Data2?
Post some sample code that constructs the data.frames and the code you  
used.
>
> I already tried write.table(), buy that wasn't it.
> And I am kinda stuck on this now.....

-- 
David Winsemius, MD
West Hartford, CT

> -----Original Message-----
> From: r-help-bounces at r-project.org [mailto:r-help-bounces at r-
> project.org] On Behalf Of Yellow
> Sent: Thursday, April 12, 2012 2:18 AM
> To: r-help at r-project.org
> Subject: [R] How insert data to a column in existing csv file?
> 
> I was working with some excel files with a lot of data.
> And by hand it is impossible to handle them.
> So they are now converted to .csv.
> 
> With headers above the columns, like:
> Data1, Data2, Data3
> 
> But now I needed to calculate the log2 value of Data1 and place the
> result
> under Data2.
> I can't find how to do that.
> Does anyone else know?
> 
> I have the log2 values, but how do I get then inside the .csv file
> under
> Data2?
> 
> I already tried write.table(), buy that wasn't it.
> And I am kinda stuck on this now.....
> 
> 
In the absence of a reproducible example, we can only guess.  My guess is that
you should read the csv file into a data frame, add or modify your variable(s),
then write out a new csv file.


Dan

Daniel J. Nordlund
Washington State Department of Social and Health Services
Planning, Performance, and Accountability
Research and Data Analysis Division
Olympia, WA 98504-5204

Hi everyone, 

I read your messages and I tried some things out. 
The Data2 is filled with NA. 
So what I did was: 

NameFile.csv$Data2[is.na(NameFile.csv$Data2)] = log2Values 

And now it worked. :) 
Seems like I needed to replace it, and not only write it. 

Thanks.  

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