I'm dealing with the following dataset

```
    animal protein herd sire dam
6      416  189.29    2   15 236
7      417  183.27    2    6 295
9      419  193.24    3   11 268
10     420  198.84    2   12 295
11     421  205.25    3    3 251
12     422  204.15    2    2 281
13     423  200.20    2    3 248
14     424  197.22    2   11 222
15     425  201.14    1   10 262
17     427  196.20    1   11 290
18     428  208.13    3    9 294
19     429  213.01    3   14 254
21     431  203.38    2    4 273
22     432  190.56    2    8 248
25     435  196.59    3    9 226
26     436  193.31    3   10 249
27     437  207.89    3    7 272
29     439  202.98    2   10 260
30     440  177.28    2    4 291
31     441  182.04    1    6 282
32     442  217.50    2    3 265
33     443  190.43    2   11 248
35     445  197.24    2    4 256
37     447  197.16    3    5 240
42     452  183.07    3    5 293
43     453  197.99    2    6 293
44     454  208.27    2    6 254
45     455  187.61    3   12 271
46     456  173.18    2    6 280
47     457  187.89    2    6 235
48     458  191.96    1    7 286
49     459  196.39    1    4 275
50     460  178.51    2   13 262
52     462  204.17    1    6 253
53     463  203.77    2   11 273
54     464  206.25    1   13 249
55     465  211.63    2   13 222
56     466  211.34    1    6 228
57     467  194.34    2    1 217
58     468  201.53    2   12 247
59     469  198.01    2    3 251
60     470  188.94    2    7 290
61     471  190.49    3    2 220
62     472  197.34    2    3 224
63     473  194.04    1   15 229
64     474  202.74    2    1 287
67     477  189.98    1    6 300
69     479  206.37    3    2 293
70     480  183.81    2   10 274
72     482  190.70    2   12 265
74     484  194.25    3    2 262
75     485  191.15    3   10 297
76     486  193.23    3   15 255
77     487  193.29    2    4 266
78     488  182.20    1   15 260
81     491  195.89    2   12 294
82     492  200.77    1    8 278
83     493  179.12    2    7 281
85     495  172.14    3   13 252
86     496  183.82    1    4 264
88     498  195.32    1    6 249
89     499  197.19    1   13 274
90     500  178.07    1    8 293
92     502  209.65    2    7 241
95     505  199.66    3    5 220
96     506  190.96    2   11 259
98     508  206.58    3    3 230
100    510  196.60    2    5 231
103    513  193.25    2   15 280
104    514  181.34    2    3 227

```

I'm interested with the animals indexes and corresponding to them the dams' indexes. Using *table* function I was able to check that some dams are matched to different animals. In fact I got the following output 

```
217 220 222 224 226 227 228 229 230 231 235 236 240 241 247 248 249 251 252 253 254 255 256 259 260 262 
  1   2   2   1   1   1   1   1   1   1   1   1   1   1   1   3   3   2   1   1   2   1   1   1   2   3 
264 265 266 268 271 272 273 274 275 278 280 281 282 286 287 290 291 293 294 295 297 300 
  1   2   1   1   1   1   2   2   1   1   2   2   1   1   1   2   1   4   2   2   1   1 

```

Using *length* function I checked that there are only 48 dams in this dataset.

I would like to 'reindex' them with the integers 1, ..., 48 instead of these given in my set. Is there any method of doing such things?