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  1. library(data.table)
  2. library(magrittr)
  3.  
  4. # fake data; 1000 rows
  5. set.seed(1234)
  6. d0 <-
  7.   data.table(
  8.     item_id = 1L:1000L,
  9.     ttl = runif(1000L),
  10.     item_category_id = sample(1L:83L, 1000L, replace = T)
  11.   )
  12.  
  13. d1 <-
  14.   d0[, .(
  15.     sum.of.ttl.by.item_category_id = sum(ttl),
  16.     raw.of.item = list(item_id),
  17.     raw.of.ttl = list(ttl)
  18.   ), by = .(item_category_id)]
  19. head(d1)
  20. #    item_category_id sum.of.ttl.by.item_category_id                 raw.of.item
  21. # 1:               75                       9.775620   1, 86,113,278,309,377,...
  22. # 2:               64                       8.876390   2, 28, 39, 41,172,269,...
  23. # 3:               66                       5.105777   3,170,195,211,230,233,...
  24. # 4:               24                       7.403771   4, 12, 57,101,183,267,...
  25. # 5:               57                       6.665990   5, 37, 73,191,259,360,...
  26. # 6:               31                       4.670723   6, 22,452,473,549,603,...
  27. #                                                                           raw.of.ttl
  28. # 1:                   0.1137034,0.8985805,0.9503049,0.5447566,0.5484554,0.7593397,...
  29. # 2:             0.62229940,0.91465817,0.99215042,0.55333359,0.58427152,0.04946115,...
  30. # 3:                   0.6092747,0.3252783,0.8100834,0.5663108,0.4944386,0.1066968,...
  31. # 4:             0.62337944,0.54497484,0.49396092,0.03545673,0.60071414,0.74816114,...
  32. # 5:             0.86091538,0.20124804,0.01462726,0.63891131,0.58951654,0.76815200,...
  33. # 6: 0.6403106053,0.3026933707,0.7759688012,0.0006121558,0.9797886356,0.1702244373,...
  34.  
  35. d1$raw.of.item[1:2]
  36. # [[1]]
  37. #  [1]   1  86 113 278 309 377 426 457 493 505 569 627 643 798 840 980 995
  38. # 
  39. # [[2]]
  40. #  [1]   2  28  39  41 172 269 286 311 431 579 668 702 768 782 828 908 942
  41.  
  42. d1$raw.of.ttl[1:2]
  43. # [[1]]
  44. #  [1] 0.1137034 0.8985805 0.9503049 0.5447566 0.5484554 0.7593397 0.1999333 0.2468865 0.9126530 0.6744341 0.2085592 0.4840459
  45. # [13] 0.5096489 0.8223393 0.6235133 0.5847833 0.6936828
  46. # 
  47. # [[2]]
  48. #  [1] 0.62229940 0.91465817 0.99215042 0.55333359 0.58427152 0.04946115 0.28077262 0.91342167 0.66349054 0.55109725 0.28465309
  49. # [12] 0.59863873 0.57321496 0.05653095 0.39876005 0.25607750 0.58355793
  50.  
Success #stdin #stdout 0.32s 43288KB
comments (?)
stdin 
Standard input is empty
stdout 
   item_category_id sum.of.ttl.by.item_category_id              raw.of.item
1:               70                       5.321331   1,216,257,280,313,318,
2:               41                       5.961307   2, 19, 57, 87,277,390,
3:               10                       9.898108   3, 71, 92,240,304,335,
4:               30                       7.860412   4, 29,106,130,179,255,
5:               64                       7.419698   5, 63,129,250,322,400,
6:               33                       6.909596   6, 65, 73,315,336,396,
                                                           raw.of.ttl
1:       0.1137034,0.9321736,0.2623557,0.3446373,0.4072514,0.4084144,
2:       0.6222994,0.1867228,0.4939609,0.3894998,0.8212286,0.9470380,
3:       0.6092747,0.1214802,0.9004246,0.9897099,0.4440339,0.4726167,
4: 0.62337944,0.83134505,0.32568192,0.31844581,0.11613577,0.06510324,
5:       0.8609154,0.3171822,0.4969662,0.7969238,0.8618053,0.3663996,
6: 0.64031061,0.23902573,0.01462726,0.14608279,0.38605066,0.92318086,
[[1]]
 [1]   1 216 257 280 313 318 341 346 462 757

[[2]]
 [1]   2  19  57  87 277 390 435 437 494 638 659 741 790

[[1]]
 [1] 0.1137034 0.9321736 0.2623557 0.3446373 0.4072514 0.4084144 0.9558402
 [8] 0.3104304 0.8947680 0.6917567

[[2]]
 [1] 0.6222994 0.1867228 0.4939609 0.3894998 0.8212286 0.9470380 0.2722072
 [8] 0.3802893 0.3080208 0.8435601 0.2581553 0.2715826 0.1667424
https://ideone.com/bvnJFr
language:
R (R 3.5.2)
created:
5 years ago
visibility:
public

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