[R] comparing elements in a vector

[John Deke]

How about --

d is a vector as you described it, then define

d1 <- d[1:(length(d)-1)]
d2 <- d[2:length(d)]
d3 <- d1!=0 & d2!=0 & (d1-d2)!=0

I think d3 is the final vector you wanted.

I didn't test it, so I'm not sure my logic is right, but I think this is
definitely a path you can take...

-----Original Message-----
From: owner-r-help at stat.math.ethz.ch
[mailto:owner-r-help at stat.math.ethz.ch]On Behalf Of Sven Garbade
Sent: Wednesday, September 18, 2002 9:35 AM
To: r-help at stat.math.ethz.ch
Subject: [R] comparing elements in a vector


Hi all,

there is a vector d which contains three different valus: 0, 1 or 2. I
wrote a loop which gives me T, when the values in d changed from 1 to
2 or from 2 to 1, otherwise F:

for(i in 1:(length(d)-1)) {
   if(d[i] != d[i+1] & d[i] != 0 & d[i+1] != 0)
      change[i+1] <- T	    
    else	  
      change[i+1] <- F
}

This works, but I'm wondering if there is already a R function or an
easier way to avoid the for-loop.

Thanks, Sven

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