R help - Sep 2010 - How to convert a character into a filename?

Dear list,

How to convert a character to a filename?
such as:

x <- "height"  # "height" here is actually a name of a
colume in a  data
frame
filename <- paste("plant,x")
write.csv (data, file="C:/plant/filename.csv)  # having trouble with this
statement, how to 'write' the filename here?

All I want from above is to write 'data' to a file named plantheight.csv

(the ultimate goal is to use a loop to transfer each column of a data frame
into a separated file named from that column
e.g. to create many files with different names but the names are all like:
plantheight.csv, plantweight.csv, and height, weight.., are column names of
a data frame)

Thank you!

Tuc Aug.

	[[alternative HTML version deleted]]

file <- foo.data

filename <- paste("plant", x, sep="")
out <- paste("C:/", "plant/", filename,
".csv",sep="")

write.csv(file, out)

On Tue, Sep 21, 2010 at 5:14 PM, Tucson August <tucsonaugust at gmail.com>
wrote:
> Dear list,
>
> How to convert a character to a filename?
> such as:
>
> x <- "height" ?# "height" here is actually a name of
a colume in a ?data
> frame
> filename <- paste("plant,x")
> write.csv (data, file="C:/plant/filename.csv) ?# having trouble with
this
> statement, how to 'write' the filename here?
>
> All I want from above is to write 'data' to a file named
plantheight.csv
>
> (the ultimate goal is to use a loop to transfer each column of a data frame
> into a separated file named from that column
> e.g. to create many files with different names but the names are all like:
> plantheight.csv, plantweight.csv, and height, weight.., are column names of
> a data frame)
>
> Thank you!
>
> Tuc Aug.
>
> ? ? ? ?[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
>


-- 
Stephen Sefick
____________________________________
| Auburn University? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? |
| Department of Biological Sciences? ? ? ? ?? |
| 331 Funchess Hall? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? |
| Auburn, Alabama? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ?? |
| 36849? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? |
|___________________________________|
| sas0025 at auburn.edu? ? ? ? ? ? ? ? ? ? ? ? ? ?? |
| http://www.auburn.edu/~sas0025? ? ? ? ? ?? |
|___________________________________|

Let's not spend our time and resources thinking about things that are
so little or so large that all they really do for us is puff us up and
make us feel like gods.? We are mammals, and have not exhausted the
annoying little problems of being mammals.

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -K. Mullis

"A big computer, a complex algorithm and a long time does not equal
science."

? ? ? ? ? ? ? ? ? ? ? ? ? ? ? -Robert Gentleman

On Sep 21, 2010, at 6:14 PM, Tucson August wrote:
> Dear list,
>
> How to convert a character to a filename?
Filenames are character mode so that shouldn't be a problem.
> such as:
>
> x <- "height"  # "height" here is actually a name of
a colume in a
> data
> frame
So you need to learn how to refer to column and that's not it.
Try:

plant["height"]
> filename <- paste("plant,x")   # Would produce
"plant,x"  ... not
> useful
write.table function takes a dataframe or matrix or something that can  
be coerce to one of those.
> write.csv (data, file="C:/plant/filename.csv  )  # having trouble  
> with this
                                              ^^
You forgot the closing quotes ... unless that is you expected the "c:/ 
plant/" and the ".csv" to be automatically prepended and appended
and
the filename you created to be substituted. That's not going to happen  
without some greater effort. You can smush together character values  
like this:

paste("c:/path/plant/", filename, ".csv", sep="")
> statement, how to 'write' the filename here?
>
> All I want from above is to write 'data' to a file named  
> plantheight.csv
>
> (the ultimate goal is to use a loop to transfer each column of a  
> data frame
> into a separated file named from that column
A column name may not be a first class object.
> e.g. to create many files with different names but the names are all  
> like:
> plantheight.csv, plantweight.csv, and height, weight.., are column  
> names of
> a data frame)
Did you read the Posting Guide that suggested a reproducible example?
>
> Thank you!
>
> Tuc Aug.
>
> 	[[alternative HTML version deleted]]
>
> ______________________________________________
> R-help at r-project.org mailing list
> https://stat.ethz.ch/mailman/listinfo/r-help
> PLEASE do read the posting guide
http://www.R-project.org/posting-guide.html
> and provide commented, minimal, self-contained, reproducible code.
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 Tucson August
> Sent: Tuesday, September 21, 2010 3:15 PM
> To: r-help at r-project.org
> Subject: [R] How to convert a character into a filename?
> 
> Dear list,
> 
> How to convert a character to a filename?
> such as:
> 
> x <- "height"  # "height" here is actually a name of
a colume in a
> data
> frame
> filename <- paste("plant,x")
> write.csv (data, file="C:/plant/filename.csv)  # having trouble with
> this
> statement, how to 'write' the filename here?
> 
> All I want from above is to write 'data' to a file named
> plantheight.csv
> 
> (the ultimate goal is to use a loop to transfer each column of a data
> frame
> into a separated file named from that column
> e.g. to create many files with different names but the names are all
> like:
> plantheight.csv, plantweight.csv, and height, weight.., are column
> names of
> a data frame)
> 
> Thank you!
> 
> Tuc Aug.
> 
For illustration purposes I will call your data frame, your.data .  You can loop
through the column names of your.data, construct an 'out' file name and
then write the data.  Something like

for(i in names(your.data)){
  out <- paste("C:/plant/plant", i,
".csv",sep="")
  write.csv(your.data[i], out, row.names=FALSE)
  }

You didn't tell us whether you wanted row names witten to the file or not,
so I decided not.  Likewise, I decided to write column names (the default).

Hope this is helpful,

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