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selecting certain rows from data frame

8 messages · Hrithik R, steven mosher, Ivan Calandra +2 more

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On 2010-12-14 23:57, steven mosher wrote:
Or use subset():

  DF2 <- subset(DF, ID %in% c(2,5))

Peter Ehlers
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Hi,

Just to note that which() is unnecessary here:
DF2 <- DF[DF$ID==2 | DF$ID==5, ]

Ivan

Le 12/15/2010 08:57, steven mosher a ?crit :

  
    
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On Dec 15, 2010, at 4:18 AM, Ivan Calandra wrote:

            
And to further note that it is only unnecessary of you have no NA's in  
that ID column.

 > DF[4,1] <- NA
 > DF[8,1] <- NA
 > DF2 <- DF[DF$ID==2 | DF$ID==5, ]

(These NA rows would not appear if which() were used.)
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On 2010-12-15 09:44, Hrithik R wrote:
That's easy; use the 'NOT' operator ('!' in R):

  DF2 <- subset(DF, !(ID %in% c(2,5)))

Peter Ehlers