[R] How to insert filename as column in a file

[jim holtman]

This might do it for you:


for (i in fileNames){
    input <- read.table(i, .....)
   # you might want to use regular expressions to extract just the date.
    input$fileName <- i
    write.table(i, ....)
}

On Mon, Apr 23, 2012 at 12:29 PM, Shivam <shivamsingh at gmail.com> wrote:
> Hi,
>
> I am relatively new to R. Have scourged the help files and the www but
> havent been able to get a solution.
>
> I have around 250 csv files, one file for each date. They have columns of
> all types, numeric, string etc. The name of each file is the date in the
> form of 'yyyymmdd'. There is no column within the file which helps me
> identify the date on which the file was generated, only the filename has
> that info.
>
> I am selecting some data (using read.csv.sql) from each file and creating a
> dataset for each day. Ultimately I will combine all the datasets. I can
> accomplish the select and combine part, but after combining I wont have a
> record as to the date corresponding to the data.
>
> Hence I want to insert the filename as a column in the respective file to
> help me in identifying to what date each data row belongs to.
>
> Sorry for the long mail, but wanted to make myself clear. Any help would be
> greatly appreciated.
>
> Thanks in advance,
> Shivam
>
>        [[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.



-- 
Jim Holtman
Data Munger Guru

What is the problem that you are trying to solve?
Tell me what you want to do, not how you want to do it.