[R] Selecting the first occurrence of a value after an occurrence of a different value

surreyj surreyjackson at gmail.com
Mon Jan 17 08:09:58 CET 2011


Hello, 

Back again, 

I thought the problem was solved but I realised that the only reason I was
getting the correct answer was because my data set happened to only have two
"rfts" to choose from, so it looked correct.

I have been using:

onlyfirstresponseafterrft<-which(!diff(as.numeric(factor(Stat, levels =
c("MagDwn", "Resp")))))
> onlyfirstresponseafterrft
  [1]  11  12  13  19  20  21  27  28  29  35  36  37  43  44  45  51  52 
53
 [19]  59  60  61  67  68  69  75  76  77  83  84  85  91  92  93 103 104
105
 [37] 113 114 115 121 122 123 129 130 131 137 138 139 145 146 147 153 154
155
 [55] 161 162 163 173 174 175 181 182 183 191 192 193 199 200 201 207 208
209
 [73] 215 216 217 225 226 227 233 234 235 241 242 243 251 252 253 259 260
261
 [91] 267 268 269 275 276 277 283 284 285 291 292 293 303 304 305 311 312
313
[109] 319 320 321 329 330 331 337 338 339

to get my results and what is being delivered is the rows at which a "resp"
occurs after a "magdwn" except I only want the first "resp" after a mag
down... This seems simple to figure out and I have tried a lot of things but
its just not happening!

Can anyone help me please?

Thanks
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