Generating vectors
> index <- 1:25
> index
[1] 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
[23] 23 24 25
> index <- 25:1
> index
[1] 25 24 23 22 21 20 19 18 17 16 15 14 13 12 11 10 9 8 7 6 5 4
[23] 3 2 1
The sequence function seq()
The function seq() together with its arguments
from, to, by or length is used to generate more general sequences. Specify the
beginning and end of the sequence and either specify the length of the sequence
or the increment
> m <- seq (from = .7, to = 6,by = 0.5)
> m
[1] 0.7 1.2 1.7 2.2 2.7 3.2 3.7 4.2 4.7 5.2 5.7
> n<-seq(from=.9,to=10,by=.10)
> n
[1] 0.9 1.0 1.1 1.2 1.3 1.4 1.5 1.6 1.7 1.8 1.9 2.0 2.1
[14] 2.2 2.3 2.4 2.5 2.6 2.7 2.8 2.9 3.0 3.1 3.2 3.3 3.4
[27] 3.5 3.6 3.7 3.8 3.9 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7
[40] 4.8 4.9 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 5.9 6.0
[53] 6.1 6.2 6.3 6.4 6.5 6.6 6.7 6.8 6.9 7.0 7.1 7.2 7.3
[66] 7.4 7.5 7.6 7.7 7.8 7.9 8.0 8.1 8.2 8.3 8.4 8.5 8.6
[79] 8.7 8.8 8.9 9.0 9.1 9.2 9.3 9.4 9.5 9.6 9.7 9.8 9.9
[92] 10.0
The following commands have the same result:
> l <-seq(.2,9,length = 14)
> l
[1] 0.2000000 0.8769231 1.5538462 2.2307692 2.9076923 3.5846154
[7] 4.2615385 4.9384615 5.6153846 6.2923077 6.9692308 7.6461538
[13] 8.3230769 9.0000000
> l<-(.2:4/2)
> l
[1] 0.1 0.6 1.1 1.6
#sum
> #
> #(i^3+4i^2) where i=10:100
> mohi<-10:100
> sum(mohi^3+4*mohi^2)
[1] 26852735
> rj<-1:25
> sum((2^rj)/rj+3*rj/(rj^2))
[1] 2807618
> #Function paste to create
> #("label 1","label 2".......,"label 30")
> paste("label",1:30)
[1] "label 1" "label 2" "label 3" "label 4"
[5] "label 5" "label 6" "label 7" "label 8"
[9] "label 9" "label 10" "label 11" "label 12"
[13] "label 13" "label 14" "label 15" "label 16"
[17] "label 17" "label 18" "label 19" "label 20"
[21] "label 21" "label 22" "label 23" "label 24"
[25] "label 25" "label 26" "label 27" "label 28"
[29] "label 29" "label 30"
> #("fn1","fn2",....,"fn30")
> paste("fn",1:30,sep="")
[1] "fn1" "fn2" "fn3" "fn4" "fn5" "fn6"
[7] "fn7" "fn8" "fn9" "fn10" "fn11" "fn12"
[13] "fn13" "fn14" "fn15" "fn16" "fn17" "fn18"
[19] "fn19" "fn20" "fn21" "fn22" "fn23" "fn24"
[25] "fn25" "fn26" "fn27" "fn28" "fn29" "fn30"
> #Creat two vectors of random integer which are chosen with replacement from the integers 0,1,2.....,999. both vectors have lengh 250
> set.seed(50)
> rVec<-sample(0:999,250,replace = T)
> qVec<-sample(0:999,250,replace = T)
> #suppose x=(x1,x2,......xn) denote rVec and y=(y1,y2....yn) denot qVec
> # creat the vector (y2-x1,......,yn-xn-1)
> qVec[-1]-rVec[-length(rVec)]
[1] -359 692 -724 40 -626 -719 -809 527 -89
[10] -829 248 144 -749 -352 -220 -249 387 -492
[19] 85 -106 303 -97 -436 146 282 -206 -385
[28] -96 -567 -757 287 277 -562 292 -89 -93
[37] -847 -822 -203 679 309 -199 -273 4 -47
[46] 142 122 414 -602 -304 -674 -8 -662 -168
[55] -349 -63 -221 115 1 -600 -382 -487 2
[64] 375 19 -113 -634 107 60 47 214 -325
[73] -49 -290 169 290 -624 457 -408 581 -189
[82] 204 -80 409 209 -410 461 37 -127 185
[91] 382 -446 44 -56 -270 -598 -378 -155 134
[100] -187 109 316 -139 158 305 -39 -119 182
[109] 441 -403 -107 615 614 -378 -464 31 -385
[118] 665 674 -217 -279 -406 -45 -489 -350 -451
[127] -18 660 504 -6 60 -130 -379 -302 -219
[136] -21 438 129 -201 -275 131 694 -96 -176
[145] 117 -113 887 -439 -126 -148 392 -158 444
[154] -291 232 -12 -274 477 -510 336 -759 -363
[163] -195 -220 160 -308 -333 302 -183 227 -12
[172] 428 665 -301 -8 222 -50 -444 -425 -650
[181] -424 318 154 238 -727 71 472 908 265
[190] 654 -644 -754 657 -382 -313 910 -381 394
[199] -596 602 397 -572 378 -274 -271 601 -791
[208] -378 -461 39 163 -118 -332 -170 -94 262
[217] -474 566 -273 -366 -400 374 42 100 135
[226] 609 -527 580 -219 128 -524 620 -206 410
[235] -280 -66 -50 252 279 48 -595 -59 -623
[244] 247 514 62 -102 475 287
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