[R] subsetting levels of a vector

[John Kane]

subset should work fine.  My guess would be that Electrode is a character or factor variable.  Use str() to see what kind of variables you have in the data set.

If we call the data set dat1 this works. 
subset(dat1,  dat1$Electrode =="FP1" | dat1$Electrode  =="FP2" | dat1$Electrode == "F4")




John Kane
Kingston ON Canada


> -----Original Message-----
> From: mancinisimona at yahoo.it
> Sent: Fri, 10 Aug 2012 10:07:31 +0100 (BST)
> To: r-help at r-project.org
> Subject: [R] subsetting levels of a vector
> 
> Hi,
> 
> 
> I need to subset different levels of vector in a dataset to create a new
> dataframe that contains only these. These observations are not numerical,
> so I can't use the subset() function (at least this is the response I get
> from R).
> Suppose the dataframe looks like this:
> 
> 
> 
>   ParticipID    ERP   Electrode
> 1         s1  0.0370       FP1
> 2         s2 35.0654       FP2
> 3         s3 -3.3852        F4
> 4         s4  2.6119        P3
> 5         s5  0.1224        P4
> 6         s6 -5.3153        O1
> 
> 
> I want to create a subset of the dataframe with only the FP1, FP2, F4
> levels of Electrode, how do I do?
> (actually the levels I have to filter are much more than these three, but
> this is just to give an example).
> 
> I know this is a trivial question, but I am still getting familiar with
> R...
> 
> Thanks a lot,
> 
> s.
> 
> 	[[alternative HTML version deleted]]
> 
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