Question

我是R的新手，但经过一段时间努力解决这个问题后，我正在寻求帮助：

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"

我想将这个矩阵子集化为其他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)]

它适用于Ls1＆amp; LS2。但是Ls3会改变格式。

> 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。

Answer 1

默认[选择尝试通过删除长度为1的维度来简化结果。如果您不想要，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

R - 矩阵子集给出了不正确的维度

1 个答案: