假设我有这些数据：
set.seed(1234)
cMat <- matrix(rnorm(10),5,2)
clist <- replicate(39, cMat + rnorm(10), simplify=FALSE)
[[1]]
[,1] [,2]
[1,] -1.6842584 0.3957704
[2,] -0.7209572 -1.0857495
[3,] 0.3081873 -1.4578273
[4,] -2.2812389 -1.4016237
[5,] 1.3886187 1.5257973
[[2]]
[,1] [,2]
[1,] -1.0729775 -9.421490e-01
[2,] -0.2132567 1.576077e-05
[3,] 0.6438933 -1.570288e+00
[4,] -1.8861083 -5.795903e-01
[5,] -0.2645956 -1.825986e+00
[[3]]
[,1] [,2]
[1,] -0.1047682 -0.6615634
[2,] -0.1981638 -2.7547796
[3,] 0.3750011 -1.8876250
[4,] -2.8469558 -0.8587459
[5,] -1.1999688 -1.3559354
[[4]]
[,1] [,2]
[1,] 0.2424305 -0.4624584
[2,] -0.7912135 -1.6820582
[3,] 0.2290765 -1.7986177
[4,] -2.6263207 -1.0882801
[5,] -0.5652154 -1.3868878
[[5]]
[,1] [,2]
[1,] -3.01309701 1.069112
[2,] -0.30464668 1.073078
[3,] -0.02444845 -1.319985
[4,] -3.36065971 1.041458
[5,] 0.26681517 -2.047846
[[6]]
[,1] [,2]
[1,] -0.5504773 2.2831403
[2,] 2.8264203 -1.7133477
[3,] 1.0496808 0.8211953
[4,] -3.0153313 0.7651128
[5,] 0.4215199 -0.5535650
[[7]]
[,1] [,2]
[1,] -1.2001729 0.3526575
[2,] -0.1780395 -1.9654409
[3,] 0.7179172 -1.2702136
[4,] -1.6974111 -0.3061902
[5,] 2.4993956 -1.2070969
[[8]]
[,1] [,2]
[1,] -1.3848557 1.20366460
[2,] 0.1074352 -0.02474261
[3,] -0.2878607 -0.94936383
[4,] -2.5194849 -0.75604577
[5,] 1.2793569 -2.08456571
[[9]]
[,1] [,2]
[1,] -1.26022457 0.8616062
[2,] 0.53262524 -1.7093480
[3,] 2.79040518 0.3315718
[4,] -1.34418445 0.4084648
[5,] -0.06645875 1.2310793
[[10]]
[,1] [,2]
[1,] -0.7925422 0.6730452
[2,] -0.1972892 -1.4710046
[3,] 1.1504347 -0.3784465
[4,] -2.8481755 -0.2094837
[5,] -0.3968739 -0.9421429
[[11]]
[,1] [,2]
[1,] -1.40300037 1.3371965
[2,] -0.37164051 -1.8190278
[3,] -0.02532605 -0.3776054
[4,] -1.49642350 0.1087143
[5,] 0.45148721 -0.9163142
[[12]]
[,1] [,2]
[1,] -1.3984579 0.5861155
[2,] -0.5044774 -1.2061493
[3,] 3.1426032 -2.0599200
[4,] -1.5951962 -1.2005518
[5,] 2.2533330 -0.6637363
[[13]]
[,1] [,2]
[1,] -0.19337540 0.1402036
[2,] 0.53017938 -0.8908583
[3,] -0.08750714 -2.4948779
[4,] -1.67698337 0.3556055
[5,] -1.22097625 -1.5129094
[[14]]
[,1] [,2]
[1,] -1.5411024 0.90532770
[2,] 1.6725771 1.08811649
[3,] 1.7211156 -0.27073845
[4,] -2.4541294 -0.05817938
[5,] 0.9428875 -0.54248585
[[15]]
[,1] [,2]
[1,] -1.5843034 1.868187
[2,] 0.3750487 -0.809361
[3,] 2.7231858 -1.600015
[4,] -3.2212902 -1.434236
[5,] 0.5508847 -1.280165
[[16]]
[,1] [,2]
[1,] -2.05441582 1.1306890
[2,] 0.01678985 1.1034658
[3,] 0.67002147 -0.6153255
[4,] -2.52874850 -0.8852919
[5,] 0.83618079 0.5809679
[[17]]
[,1] [,2]
[1,] 0.4972636 -0.3315265
[2,] 0.3206733 -1.6985028
[3,] 0.7517839 2.4971340
[4,] -4.1679331 -0.3294307
[5,] 1.8403871 -0.9232964
[[18]]
[,1] [,2]
[1,] -3.9392853 2.4897881
[2,] 0.1776387 0.5943686
[3,] 2.0604729 -1.0553689
[4,] -1.9318288 0.1397282
[5,] 1.3414469 -1.0884541
[[19]]
[,1] [,2]
[1,] -1.7451365 1.00675051
[2,] -2.5783294 0.04547024
[3,] 0.2947943 -1.51253507
[4,] -1.8578831 -0.40179729
[5,] 2.5971572 -2.96827537
[[20]]
[,1] [,2]
[1,] -0.7218389 1.266518
[2,] 0.9741980 1.267724
[3,] 1.2699551 0.565731
[4,] -1.6449642 -0.531788
[5,] 0.7408057 -2.004487
[[21]]
[,1] [,2]
[1,] -0.7890079 0.9280643
[2,] -0.1228060 -0.7264765
[3,] 2.5779343 -1.1527830
[4,] -3.9527786 -0.8691731
[5,] 0.0133729 -0.2605017
[[22]]
[,1] [,2]
[1,] -0.3118938 -0.1537142
[2,] 0.9376419 2.3444002
[3,] 3.3579247 0.1307836
[4,] -1.1722001 -1.2487723
[5,] 0.7168344 -0.7035457
[[23]]
[,1] [,2]
[1,] -1.531459050 -0.5714862
[2,] 0.002725024 -3.8078921
[3,] 0.150937836 -0.8015065
[4,] -2.228852358 -0.5349342
[5,] 0.748284927 -0.2957641
[[24]]
[,1] [,2]
[1,] -1.1479306 0.7577070
[2,] 0.6908281 0.7825345
[3,] -0.0133310 -0.1421634
[4,] -1.6345224 -0.3000877
[5,] 1.1480134 -0.6219939
[[25]]
[,1] [,2]
[1,] -0.7701352 0.1355584
[2,] 1.3375531 0.9022296
[3,] 1.5366316 -1.7705356
[4,] -1.6824991 -0.3063836
[5,] -0.7072489 -0.4850350
[[26]]
[,1] [,2]
[1,] -0.23126243 -0.1605091
[2,] -0.07144749 -0.8133866
[3,] 1.24306662 -1.7343971
[4,] -4.10895277 -0.1795167
[5,] 0.76772074 -0.2234583
[[27]]
[,1] [,2]
[1,] -1.511680 -0.1450577
[2,] 2.102440 0.2338793
[3,] 1.755001 0.4399488
[4,] -1.397065 -0.5706228
[5,] 2.478528 -0.5709855
[[28]]
[,1] [,2]
[1,] -2.2188877 0.8254534
[2,] 0.7475968 -1.4212626
[3,] 0.3834708 -0.7923950
[4,] -1.5320148 -2.1173110
[5,] -0.3823061 -0.7616038
[[29]]
[,1] [,2]
[1,] -0.2216224 2.3158613
[2,] 0.4606768 -1.7497767
[3,] -0.6817880 -0.9133351
[4,] -2.9662314 -0.2108266
[5,] 2.0851677 -0.5708816
[[30]]
[,1] [,2]
[1,] -1.7870227 -0.1429723
[2,] -0.6758495 -1.0791142
[3,] 0.9050126 1.0677596
[4,] -1.3358895 -1.0114118
[5,] 0.4527513 -0.1268611
[[31]]
[,1] [,2]
[1,] 0.26465294 1.7337730
[2,] 0.72109415 -0.7242935
[3,] 0.66271931 1.0033515
[4,] -2.38569933 -1.1260645
[5,] -0.06315528 -1.5371551
[[32]]
[,1] [,2]
[1,] -1.0639336 -0.2105208
[2,] 0.3016179 0.5078710
[3,] 0.5799897 -1.4993173
[4,] -3.9270945 0.5620307
[5,] 0.4591911 -1.5390808
[[33]]
[,1] [,2]
[1,] -0.9145957 -0.6291570
[2,] 1.1761320 -0.8448196
[3,] 0.5656988 1.0731580
[4,] -1.7912592 -0.7785832
[5,] 0.3411510 -1.7078203
[[34]]
[,1] [,2]
[1,] -1.2610887 1.670631
[2,] 0.6075709 -1.339000
[3,] 2.0397658 -2.891145
[4,] -1.2017378 -1.036135
[5,] 0.5296471 -1.405893
[[35]]
[,1] [,2]
[1,] -3.523102 1.0535801
[2,] 0.839901 1.3164871
[3,] 0.300666 -1.4247090
[4,] -2.571752 -0.6770109
[5,] -1.157978 1.0586752
[[36]]
[,1] [,2]
[1,] -0.27324942 1.9406296
[2,] 2.19048866 -1.8605785
[3,] 1.07920712 -0.2393176
[4,] -2.49795775 -0.6107705
[5,] -0.08050697 1.3618040
[[37]]
[,1] [,2]
[1,] -1.8150995 0.63834698
[2,] -1.2318589 -0.85026471
[3,] 1.3170729 -1.22539050
[4,] -2.3853464 -0.06361607
[5,] -0.4100004 -1.22170014
[[38]]
[,1] [,2]
[1,] -3.0420460 1.7211095
[2,] -2.3743120 0.4077655
[3,] 0.5038590 -0.2308678
[4,] -0.8915108 -2.0715146
[5,] 1.2672541 -0.6844680
[[39]]
[,1] [,2]
[1,] 0.3901623 1.29545030
[2,] -3.1186343 -0.11764045
[3,] 0.3030889 -0.00779874
[4,] -1.2432331 -0.54980888
[5,] 0.9578697 -1.80652696
这个简单的功能
testfunction <- function(X)
{
newX <- X[c(1:5),]*2
return(newX)
}
然后我在此代码中使用它将其应用于列表中的每个矩阵：clistnew <- lapply(clist, testfunction)
我想添加一个条件 - 我希望以下序列中的矩阵行乘以3而不是2：
mysequence = seq(8,length(clist) ,by=13)
[1] 8 21 34
我认为将代码更改为可以正常工作
testfunction <- function(X)
{
newX <- X[c(1:5),]*2
for(i in seq(8,length(X) ,by=13)){
newX <- X[c(1:5),]*3
}
return(newX)
}
但是它将所有矩阵的行乘以3，忽略前面的代码行。我确信解决方案很简单，但我只是一个初学者，不幸的是我无法弄明白。
答案 0 :(得分：1)
如果我理解正确，以下将做你想要的。
testfunction <- function(i, X, myseq){
if(i %in% myseq)
newX <- X[1:5, ]*3
else
newX <- X[1:5, ]*2
newX
}
mysequence = seq(8, length(clist), by = 13)
lapply(seq_along(clist), function(i) testfunction(i, clist[[i]], mysequence))