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I have a vector with a length of about 3000. I highlighted a specific point in the vector with which(...). Now I want to have -120 beforethis point and +120 afterthis point.

My list is as follows:

> testList$Date

     [1] "01.01.2002" "02.01.2002" "03.01.2002" "04.01.2002" "07.01.2002"
       [6] "08.01.2002" "09.01.2002" "10.01.2002" "11.01.2002" "14.01.2002"
      [11] "15.01.2002" "16.01.2002" "17.01.2002" "18.01.2002" "21.01.2002"
      [16] "22.01.2002" "23.01.2002" "24.01.2002" "25.01.2002" "28.01.2002"
      [21] "29.01.2002" "30.01.2002" "31.01.2002" "01.02.2002" "04.02.2002"
      [26] "05.02.2002" "06.02.2002" "07.02.2002" "08.02.2002" "11.02.2002"
      [31] "12.02.2002" "13.02.2002" "14.02.2002" "15.02.2002" "18.02.2002"ect....

I could do for-loopto iterate over the list and save it as a sublist. However, I do not think it is very effective. How can I implement this in R?

I appreciate your answer!

UPDATE When using, lapplyI get:

> 120BeforeSublist <- lapply(event, function(x) c(x-120, x))
> (120BeforeSublist)
[[1]]
[1] 1875 1995

However, I want to keep a sublist -120 before and +120 after.

+4
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2 answers

Does this describe your problem in principle and a general solution:

x <- 1:20
pos <- which( x == 10 )
end <- 2
len <- 5
x_bef <- x[ ( pos - len - end ) : ( pos - end ) ]
x_aft <- x[ (pos + end ) : ( pos + len + end ) ] 

x_bef
[1] 3 4 5 6 7 8
x_aft
[1] 12 13 14 15 16 17
+3
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How about something like this:

i <- which(...)
boundaries <- lapply(i, function(x) (x-120):(x+120))

Example:

> i <- c(350, 465, 2700) # Points of interest
> boundaries <- lapply(i, function(x) (x-120):(x+120))
> boundaries
[[1]]
  [1] 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247
 [19] 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265
 [37] 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283
 [55] 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301
 [73] 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 318 319
 [91] 320 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337
[109] 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355
[127] 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373
[145] 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391
[163] 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409
[181] 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427
[199] 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445
[217] 446 447 448 449 450 451 452 453 454 455 456 457 458 459 460 461 462 463
[235] 464 465 466 467 468 469 470

[[2]]
  [1] 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362
 [19] 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380
 [37] 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398
 [55] 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416
 [73] 417 418 419 420 421 422 423 424 425 426 427 428 429 430 431 432 433 434
 [91] 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452
[109] 453 454 455 456 457 458 459 460 461 462 463 464 465 466 467 468 469 470
[127] 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488
[145] 489 490 491 492 493 494 495 496 497 498 499 500 501 502 503 504 505 506
[163] 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524
[181] 525 526 527 528 529 530 531 532 533 534 535 536 537 538 539 540 541 542
[199] 543 544 545 546 547 548 549 550 551 552 553 554 555 556 557 558 559 560
[217] 561 562 563 564 565 566 567 568 569 570 571 572 573 574 575 576 577 578
[235] 579 580 581 582 583 584 585

[[3]]
  [1] 2580 2581 2582 2583 2584 2585 2586 2587 2588 2589 2590 2591 2592 2593 2594
 [16] 2595 2596 2597 2598 2599 2600 2601 2602 2603 2604 2605 2606 2607 2608 2609
 [31] 2610 2611 2612 2613 2614 2615 2616 2617 2618 2619 2620 2621 2622 2623 2624
 [46] 2625 2626 2627 2628 2629 2630 2631 2632 2633 2634 2635 2636 2637 2638 2639
 [61] 2640 2641 2642 2643 2644 2645 2646 2647 2648 2649 2650 2651 2652 2653 2654
 [76] 2655 2656 2657 2658 2659 2660 2661 2662 2663 2664 2665 2666 2667 2668 2669
 [91] 2670 2671 2672 2673 2674 2675 2676 2677 2678 2679 2680 2681 2682 2683 2684
[106] 2685 2686 2687 2688 2689 2690 2691 2692 2693 2694 2695 2696 2697 2698 2699
[121] 2700 2701 2702 2703 2704 2705 2706 2707 2708 2709 2710 2711 2712 2713 2714
[136] 2715 2716 2717 2718 2719 2720 2721 2722 2723 2724 2725 2726 2727 2728 2729
[151] 2730 2731 2732 2733 2734 2735 2736 2737 2738 2739 2740 2741 2742 2743 2744
[166] 2745 2746 2747 2748 2749 2750 2751 2752 2753 2754 2755 2756 2757 2758 2759
[181] 2760 2761 2762 2763 2764 2765 2766 2767 2768 2769 2770 2771 2772 2773 2774
[196] 2775 2776 2777 2778 2779 2780 2781 2782 2783 2784 2785 2786 2787 2788 2789
[211] 2790 2791 2792 2793 2794 2795 2796 2797 2798 2799 2800 2801 2802 2803 2804
[226] 2805 2806 2807 2808 2809 2810 2811 2812 2813 2814 2815 2816 2817 2818 2819
[241] 2820
+1
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