[R] how to drop rows from a data.frame

Patrick Connolly p.connolly at hortresearch.co.nz
Thu Jul 1 06:13:40 CEST 2004


On Wed, 30-Jun-2004 at 11:57PM -0400, Peter Wilkinson wrote:

|> here is a snippet of data where I would like to drop all rows that have 
|> zeros across them, and keep the rest of the rows while maintaining the row 
|> names (1,2,3, ...10). The idea here is that a row of zeros is an indication 
|> that the row must be dropped. There will never be the case where there is a 
|> row(of n columns) with less than 5 zeros in this case(n zeros
|> 
|> I am unsure how to manipulate the data frame to drop rows whiles keeping 
|> row names.
|> 
|> Peter
|> 
|> the data (imagine separated by tabs):
|> 
|>        SEKH0001  SEKH0002 SEKH0003 SEKH0004 SEKH0005
|>   [1,] 256.1139  256.1139 256.1139 256.1139 256.1139
|>   [2,] 283.0741  695.1000 614.5117 453.0342 500.1436
|>   [3,] 257.3578  305.0818 257.3578 257.3578 257.3578
|>   [4,]   0.0000    0.0000   0.0000   0.0000   0.0000
|>   [5,]   0.0000    0.0000   0.0000   0.0000   0.0000
|>   [6,]   0.0000    0.0000   0.0000   0.0000   0.0000
|>   [7,]   0.0000    0.0000   0.0000   0.0000   0.0000
|>   [8,] 257.0000  257.0000 257.0000 257.0000 257.0000
|>   [9,] 305.7857 2450.0417 335.5428 305.7857 584.2485
|> [10,]   0.0000    0.0000   0.0000   0.0000   0.0000

I'm curious to know how you got those row names.  I suspect you really
have a matrix.

If it were a dataframe, it would behave exactly how you are reqesting
-- depending on how you got rid of rows 4:7.

Try as.data.frame(<whatever.your.data.is.now>)

Then deleting the rows will look like:

  SEKH0001  SEKH0002 SEKH0003 SEKH0004 SEKH0005
1 256.1139  256.1139 256.1139 256.1139 256.1139
2 283.0741  695.1000 614.5117 453.0342 500.1436
3 257.3578  305.0818 257.3578 257.3578 257.3578
8 257.0000  257.0000 257.0000 257.0000 257.0000
9 305.7857 2450.0417 335.5428 305.7857 584.2485


HTH


-- 
Patrick Connolly
HortResearch
Mt Albert
Auckland
New Zealand 
Ph: +64-9 815 4200 x 7188
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