Is there a way to subset a MatrixTable by rows from row i up to n? What about HailTable?
Sure:
In [5]: import hail as hl
...: ht = hl.utils.range_table(50000, n_partitions=50000)
...: n_rows = 50000
...: i = 50
...: n = 30
...: ht.tail(n_rows - i).head(n).show()
+-------+
| idx |
+-------+
| int32 |
+-------+
| 50 |
| 51 |
| 52 |
| 53 |
| 54 |
| 55 |
| 56 |
| 57 |
| 58 |
| 59 |
| 60 |
| 61 |
| 62 |
| 63 |
| 64 |
| 65 |
| 66 |
| 67 |
| 68 |
| 69 |
| 70 |
| 71 |
| 72 |
| 73 |
| 74 |
| 75 |
| 76 |
| 77 |
| 78 |
| 79 |
+-------+
EDIT: Forgot MTs. It’s the same for MTs:
In [7]: import hail as hl
...: mt = hl.utils.range_matrix_table(n_rows=50000, n_cols=10, n_partitions=50000)
...: mt = mt.annotate_entries(x = mt.row_idx * mt.col_idx)
...: n_rows = 50000
...: i = 50
...: n = 30
...: mt.tail(n_rows - i).head(n).show()
+---------+-------+-------+-------+-------+-------+-------+-------+-------+-------+-------+
| row_idx | 0.x | 1.x | 2.x | 3.x | 4.x | 5.x | 6.x | 7.x | 8.x | 9.x |
+---------+-------+-------+-------+-------+-------+-------+-------+-------+-------+-------+
| int32 | int32 | int32 | int32 | int32 | int32 | int32 | int32 | int32 | int32 | int32 |
+---------+-------+-------+-------+-------+-------+-------+-------+-------+-------+-------+
| 50 | 0 | 50 | 100 | 150 | 200 | 250 | 300 | 350 | 400 | 450 |
| 51 | 0 | 51 | 102 | 153 | 204 | 255 | 306 | 357 | 408 | 459 |
| 52 | 0 | 52 | 104 | 156 | 208 | 260 | 312 | 364 | 416 | 468 |
| 53 | 0 | 53 | 106 | 159 | 212 | 265 | 318 | 371 | 424 | 477 |
| 54 | 0 | 54 | 108 | 162 | 216 | 270 | 324 | 378 | 432 | 486 |
| 55 | 0 | 55 | 110 | 165 | 220 | 275 | 330 | 385 | 440 | 495 |
| 56 | 0 | 56 | 112 | 168 | 224 | 280 | 336 | 392 | 448 | 504 |
| 57 | 0 | 57 | 114 | 171 | 228 | 285 | 342 | 399 | 456 | 513 |
| 58 | 0 | 58 | 116 | 174 | 232 | 290 | 348 | 406 | 464 | 522 |
| 59 | 0 | 59 | 118 | 177 | 236 | 295 | 354 | 413 | 472 | 531 |
| 60 | 0 | 60 | 120 | 180 | 240 | 300 | 360 | 420 | 480 | 540 |
| 61 | 0 | 61 | 122 | 183 | 244 | 305 | 366 | 427 | 488 | 549 |
| 62 | 0 | 62 | 124 | 186 | 248 | 310 | 372 | 434 | 496 | 558 |
| 63 | 0 | 63 | 126 | 189 | 252 | 315 | 378 | 441 | 504 | 567 |
| 64 | 0 | 64 | 128 | 192 | 256 | 320 | 384 | 448 | 512 | 576 |
| 65 | 0 | 65 | 130 | 195 | 260 | 325 | 390 | 455 | 520 | 585 |
| 66 | 0 | 66 | 132 | 198 | 264 | 330 | 396 | 462 | 528 | 594 |
| 67 | 0 | 67 | 134 | 201 | 268 | 335 | 402 | 469 | 536 | 603 |
| 68 | 0 | 68 | 136 | 204 | 272 | 340 | 408 | 476 | 544 | 612 |
| 69 | 0 | 69 | 138 | 207 | 276 | 345 | 414 | 483 | 552 | 621 |
| 70 | 0 | 70 | 140 | 210 | 280 | 350 | 420 | 490 | 560 | 630 |
| 71 | 0 | 71 | 142 | 213 | 284 | 355 | 426 | 497 | 568 | 639 |
| 72 | 0 | 72 | 144 | 216 | 288 | 360 | 432 | 504 | 576 | 648 |
| 73 | 0 | 73 | 146 | 219 | 292 | 365 | 438 | 511 | 584 | 657 |
| 74 | 0 | 74 | 148 | 222 | 296 | 370 | 444 | 518 | 592 | 666 |
| 75 | 0 | 75 | 150 | 225 | 300 | 375 | 450 | 525 | 600 | 675 |
| 76 | 0 | 76 | 152 | 228 | 304 | 380 | 456 | 532 | 608 | 684 |
| 77 | 0 | 77 | 154 | 231 | 308 | 385 | 462 | 539 | 616 | 693 |
| 78 | 0 | 78 | 156 | 234 | 312 | 390 | 468 | 546 | 624 | 702 |
| 79 | 0 | 79 | 158 | 237 | 316 | 395 | 474 | 553 | 632 | 711 |
+---------+-------+-------+-------+-------+-------+-------+-------+-------+-------+-------+
tail and head for MatrixTables also support an n_cols argument.
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