How can I generate two consecutive vectors of numbers in a loop?

I have the number of trees in a hectare (400) and I want to number them. I know that the species "a" is 80% of the hectare, while species "b" is 20% of the hectare.

In a loop similar to the one below (this is a simplification of a much more complex code), the first round of the loop should create a numeric vector from 1 to 320, in the second round it should create a numeric vector from 321 to 400.

percentage <- c(.8, .2) 
init_density <- 400

for (s in 1:length(percentage)) {
        #number the trees
        temp <- vector(1:init_density, length= init_density*percentage[s])
}

Or is there a way to create the two vectors automatically given the first two variables?

Solution

Maybe this:

#Data
percentage <- c(.5, 0.3,0.2)
n <- 400
vals <- cumsum(n*percentage)
vals2 <- c(1,vals[-length(vals)]+1)
#Store
List <- list()
#Loop
for(i in 1:length(vals))
{
  List[[i]] <- seq(vals2[i],vals[i],by = 1)
}
#Print
List

Output:

List
[[1]]
  [1]   1   2   3   4   5   6   7   8   9  10  11  12  13  14  15  16  17  18  19
 [20]  20  21  22  23  24  25  26  27  28  29  30  31  32  33  34  35  36  37  38
 [39]  39  40  41  42  43  44  45  46  47  48  49  50  51  52  53  54  55  56  57
 [58]  58  59  60  61  62  63  64  65  66  67  68  69  70  71  72  73  74  75  76
 [77]  77  78  79  80  81  82  83  84  85  86  87  88  89  90  91  92  93  94  95
 [96]  96  97  98  99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114
[115] 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133
[134] 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152
[153] 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171
[172] 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190
[191] 191 192 193 194 195 196 197 198 199 200

[[2]]
  [1] 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219
 [20] 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238
 [39] 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257
 [58] 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276
 [77] 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295
 [96] 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314
[115] 315 316 317 318 319 320

[[3]]
 [1] 321 322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340
[21] 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360
[41] 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380
[61] 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400