CODEWITHSUNDEEP
rdebugging
AKshayKulkarni
AKshayKulkarni

Reputation: 57

inconsistency in a for loop with lists

I have downloaded the historical stock prices of a list of 218 stocks. I want check whether it is populated with the the most recent date or not. I have written a function to that effect, by name check.date

function(snlq){
     j <- 1;
     for(i in 1:length(snlq)){
         ind <- index(snlq[[i]])
         if(identical(ind[length(ind)],"2018-05-04") == FALSE){
                  s[j] <- i
                  j <- j+1
         }
      }
      return(s);
}

snlq is list of stocks with length 218 and of class list

But when I run it, I get the following output:

check.date(snlq)
  [1]   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18  19  20  21  22  23  24  25  26  27  28  29  30  31  32
 [33]  33  34  35  36  37  38  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57  58  59  60  61  62  63  64
 [65]  65  66  67  68  69  70  71  72  73  74  75  76  77  78  79  80  81  82  83  84  85  86  87  88  89  90  91  92  93  94  95  96
 [97]  97  98  99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128
[129] 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160
[161] 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192
[193] 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 356 358 359 360 361 362
[225] 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394
[257] 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426
[289] 427 428 429 430 431 432 433 434 435 436 437 438 439 440 441 442 443 444 445 446 447 448 449 450 451 452 453 454 455 456 457 458
[321] 459 460 461 462 463 464 465 466 467 468 469 470

How can the output be of length more than 218? Also I have checked that snlq[[1]] is up to date; then why is 1 in the output?

This might seem like a simple for loop problem, but is perplexing me.

Very many thanks for your time and effort...

Upvotes: 0

Views: 62

Answers (2)

Melissa Key
Melissa Key

Reputation: 4551

I cannot check this result without a reproducible example, but I think this will simplify your function greatly.

check.data <- function(input, today) {
  result <- sapply(input, function(x) {
    ind <- index(x)
    !identical(ind[length(ind)], today)
  })

  which(result)
}

Upvotes: 0

MKR
MKR

Reputation: 20085

It seems the problem is that s is not created in scope in which it is updated and used. @Dave2e has correctly pointed out in above comment. The most logical error seems to me is that s has been created in global space that's why your function is not giving error, otherwise your function would have not run.

There are many ways to fix the problem. One of the option can be as:

check.date <- function(snlq){
  j <- 1;
  ss <- integer()  #declare before use in function scope
  for(i in 1:length(snlq)){
    ind <- index(snlq[[i]])
    if(identical(ind[length(ind)],"2018-05-04") == FALSE){
      s = c(s,j)  #Kind of adding an element to vector s
      j <- j+1
    }
  }
  return(s);
}

Upvotes: 1

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