title: How to pull out ids in R that are interlinked?
body: <p>I have two columns id1 and id2 which have interconnected list of id's. I am looking for a solution in R that can pull those id's together based on their relationship. The basic idea is that the id's 313-320 are all interlinked, e.g. 313 linked to 314 (row1) and because 314 is linked to 316 (row 7) so 313 and 316 are also linked and so on. The solution somehow has to explore these linkages and put them together in a chain such that 313-320 will be in one and 321-328 will be in a second one.</p>
  <pre><code>id1&lt;-c(313,313,313,313,313,314,314,314,314,315,317,317,317,318,318,319,321,321,321,321,321,321,321,322,322,322,322,322, 322,323,323,323,323,323,324,324,324,324,325,325,325,326,326,327)
  
  id2&lt;-c(314,315,316,319,320,315,316,319,320,316,318,319,320,319,320,320,322,323,324,325,326,327,328,323,324,325,326,327, 328,324,325,326,327,328,325,326,327,328,326,327,328,327,328,328)
  
  df&lt;-cbind.data.frame(id1, id2)
  
  &gt; df
     id1 id2
  1  313 314
  2  313 315
  3  313 316
  4  313 319
  5  313 320
  6  314 315
  7  314 316
  8  314 319
  9  314 320
  10 315 316
  11 317 318
  12 317 319
  13 317 320
  14 318 319
  15 318 320
  16 319 320
  17 321 322
  18 321 323
  19 321 324
  20 321 325
  21 321 326
  22 321 327
  23 321 328
  24 322 323
  25 322 324
  26 322 325
  27 322 326
  28 322 327
  29 322 328
  30 323 324
  31 323 325
  32 323 326
  33 323 327
  34 323 328
  35 324 325
  36 324 326
  37 324 327
  38 324 328
  39 325 326
  40 325 327
  41 325 328
  42 326 327
  43 326 328
  44 327 328
  </code></pre>
  <p>Greatly appreciate an input here how this can be achieved?</p>