R help - Mar 2009 - How to: Read Multi-filtes and sort to different files

new R user has a question: 

I have several hundreds of .txt files from  different monitoring sites over
several years.
(1) different site has a unique name( such as : ST2.20090321.txt = Sation 2 
2009 March 21 data, ST3.20090322=Station3, 2009, March 22 data).
(2) different site has different file header, but for the same site, the header
is the same.
for example: 
Sation 2 
date time wind CO2 
2009 10:30 2 3 
station 3
data time solar NO
2009 10:20 4 5

Question: 
How to write a "R" program to read all these files, and combine the
data from each station to one file (such as: ST2.master will save all the data
from station 2, and ST1.master will save all the data from station 1) ?


Thanks a million times!

Jeff 


      
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Dear Mr. Li,

To make things simpler, you could place the files corresponding to
different stations in different directories. Then:

1) I would loop over the directories.

2) I would use dir and loop through the resulting vector (that would
contain the file names).

3) I would use read.table with parameters skip (to skip the header) and
the header option set to true.

4) I would aggregate the resulting files in a single big file.

There are ways to do that. Some involve using for loops; you can also
use sapply to loop over files and cbind if you feel confident with a
command similar to

do.call( cbind, sapply( dir(), read.table, skip = 1, header = TRUE ) )

I have not been able to test the expression above and it may not even
parse in R but it is close to something that should work.

Best regards,

Carlos J. Gil Bellosta
http://www.datanalytics.com


On Wed, 2009-03-25 at 14:30 -0700, Qianfeng Li wrote:
> new R user has a question: 
> 
> I have several hundreds of .txt files from  different monitoring sites over
several years.
> (1) different site has a unique name( such as : ST2.20090321.txt = Sation 2
2009 March 21 data, ST3.20090322=Station3, 2009, March 22 data).
> (2) different site has different file header, but for the same site, the
header is the same.
> for example: 
> Sation 2 
> date time wind CO2 
> 2009 10:30 2 3 
> station 3
> data time solar NO
> 2009 10:20 4 5
> 
> Question: 
> How to write a "R" program to read all these files, and combine
the data from each station to one file (such as: ST2.master will save all the
data from station 2, and ST1.master will save all the data from station 1) ?
> 
> 
> Thanks a million times!
> 
> Jeff 
> 
> 
>       
> 	[[alternative HTML version deleted]]
> 
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