2015-10-16 75 views
-1

我就为r的新手,但这个问题挣扎了一段时间后,我在寻找帮助:r - 矩阵的子集给出了不正确的尺寸

我有一个矩阵:

> is.matrix(Ls) 
[1] TRUE 

> Ls 
     Start  Duration 
     newrow_fin "1014507296" "133.313" 
     newrow_fin "1014657293" "449.975" 
     newrow_fin "1015523823" "566.614" 
     newrow_fin "1017473690" "233.236" 

而且我想这个矩阵子集到其他3个矩阵:

> int2_start 
[1] 1014174109 
> int3_start 
[1] 1016639945 
Ls1<-subset.matrix(Ls, (Ls[,1])<=int2_start) [,c(1,2)] 
Ls2<-subset.matrix(Ls, (Ls[,1])>int2_start) [,c(1,2)] 
Ls2<-subset.matrix(Ls2, (Ls2[,1])<=int3_start) [,c(1,2)] 
Ls3<-subset.matrix(Ls, (Ls[,1])>int3_start) [,c(1,2)] 

它工作正常的值Ls1 & Ls2中。但Ls3更改格式。

> Ls1 
Start Duration 
> Ls2 
     Start  Duration 
     newrow_fin "1014507296" "133.313" 
     newrow_fin "1014657293" "449.975" 
     newrow_fin "1015523823" "566.614" 
> Ls3 
    Start  Duration 
     "1017473690" "233.236" 
> is(Ls1) 
[1] "matrix" "array"  "structure" "vector" 
> is(Ls2) 
[1] "matrix" "array"  "structure" "vector" 
> is(Ls3) 
[1] "character"   "vector"    "data.frameRowLabels" "SuperClassMethod" 

我不明白。

+2

您的矩阵中有任何数字。只有字符。 – 2015-10-16 09:12:09

+0

如果我将代码更改为Ls2 <-subset.matrix(Ls,as.numeric(Ls [,1])> int2_start)[,c(1,2)]。同样的问题 – sugarinthemoustache

+1

它应该像'LS < - as.numeric(LS)' – 2015-10-16 09:25:37

回答

0

默认情况下,[选择尝试通过删除长度为1的维度来简化结果。如果不需要,请添加drop = FALSE

test <- array(1, dim = rep(2, 3)) 
dim(test) # 3 dimensions 
dim(test[1, ,]) # 2 dimensions 
dim(test[1, 1,]) # 1 dimension 
dim(test[1, , , drop = FALSE]) # 3 dimensions 
dim(test[1, 1, , drop = FALSE]) # 3 dimensions