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help - extract data using column names

4 messages · alex_123, jim holtman, Jessica Streicher +1 more

#
hello , I am new user in R . I have datafile (class = data.frame) which has
825 columns with unique column name i want extract 200 selected column from
datafile how can I do this?
my datafile look like..
            Mi         RBN         RBF        nDB         nX
3   2.6225979  0.53132756 -0.80599902 -1.4471864 -0.5705269
10  0.4818746 -1.72143092 -2.19579027  2.0118824 -0.5705269
12  2.8519611  1.88298265  0.09614617  0.6282549 -0.5705269
20  0.6347834 -0.36977583  0.63255683  1.3200687 -0.5705269


I want to extract data with unique name of column  , by  "Mi","RBF" etc . I
have stored character vector of desired column names. eg  aa =
c("Mi","RBF",..)





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#
Is this what you want:
+ 3   2.6225979  0.53132756 -0.80599902 -1.4471864 -0.5705269
+ 10  0.4818746 -1.72143092 -2.19579027  2.0118824 -0.5705269
+ 12  2.8519611  1.88298265  0.09614617  0.6282549 -0.5705269
+ 20  0.6347834 -0.36977583  0.63255683  1.3200687 -0.5705269", header = TRUE)
Mi         nX
3  2.6225979 -0.5705269
10 0.4818746 -0.5705269
12 2.8519611 -0.5705269
20 0.6347834 -0.5705269
On Tue, Oct 30, 2012 at 10:09 AM, alex_123 <deepak.juit at gmail.com> wrote:

  
    
#
A look at the tutorial might help here, but anyway:

Say you have that dataframe down there with the name myData (you should use dput() to give us the data btw),

then you can subset that by using myData[rows,columns], where left of the comma you define which rows you want, and right of the comma is which columns you want. If you leave it blank, all will be selected.

So you want all rows from the columns, which names are in aa, then you would write

myData[ , aa]
On 30.10.2012, at 15:09, alex_123 wrote:

            
#
Please read the Introduction to R tutorial that ships with R to get
started with R. Quoting Rolf Turner:

" Learn something about R; don't just hammer and hope.  Read the
introductory manuals and scan the FAQ."

Cheers,
Bert
On Tue, Oct 30, 2012 at 7:09 AM, alex_123 <deepak.juit at gmail.com> wrote: