[R] problem formatting data frames

Don MacQueen macq at llnl.gov
Wed Jul 17 19:58:21 CEST 2002


Have you looked at the help page for read.table, and noticed the 
comment.char and colClasses arguments?

If the rows of text have sufficient consistency you might be able to 
use comment.char option.

You could try the colClasses option to force it to read the columns 
as numerical, in which case the non-numeric data should be coerced to 
NA.

If you are on a unix machine, or have a windows machine with unix 
tools installed, you could use pipe() to pipe the files through, for 
example, a sed script that tosses any rows with non-numeric 
characters (other than 'E' if there is any data formatted in 
scientific notation).

-Don

At 10:01 AM -0400 7/17/02, VBMorozov at lbl.gov wrote:
>  Dear R-guRus:
>I have a problem with the format of my data in R.
>Let's say I have a HUGE text table which consists of columns of
>numerical data, separated by tabs, but in some places rows of text
>(error messages, etc) are inserted in between rows of numerical data.
>Because the data file is so huge and because I have thousands of these
>files, it's unpractical to try and go thru these files manually and
>remove text rows - I'd like R to do it for me.
>The following command works:
>
>MyDataFrame<-data.frame(read.table("MyFile"))
>
>but instead of numerical data in my frame I get "factor" data, because
>of these text inserts. How do I filter them out??
>
>Thank you very much,
>Vlad.
>
>
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-- 
--------------------------------------
Don MacQueen
Environmental Protection Department
Lawrence Livermore National Laboratory
Livermore, CA, USA
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