[R] help - extract data using column names

[Jessica Streicher]

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:

> 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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