This little example might help.
> foo <- data.frame(a=1:10, b=letters[1:0])
> foo
a b
1 1 a
2 2 a
3 3 a
4 4 a
5 5 a
6 6 a
7 7 a
8 8 a
9 9 a
10 10 a
> foo$date <- '20120423'
> foo
a b date
1 1 a 20120423
2 2 a 20120423
3 3 a 20120423
4 4 a 20120423
5 5 a 20120423
6 6 a 20120423
7 7 a 20120423
8 8 a 20120423
9 9 a 20120423
10 10 a 20120423
In other words, immediately after reading the data into a data frame, add
a date column as in the example. You'll have to extract the date from the
filename, of course.
-Don
--
Don MacQueen
Lawrence Livermore National Laboratory
7000 East Ave., L-627
Livermore, CA 94550
925-423-1062
On 4/23/12 9:29 AM, "Shivam" <shivamsi...@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]]
>
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>and provide commented, minimal, self-contained, reproducible code.
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