为什么matrix()和array()返回的对象的类和模式相同?
下面是我的大数据文件的前几行:为什么matrix()和array()返回的对象的类和模式相同?,r,class,R,Class,下面是我的大数据文件的前几行: Symbol|Security Name|Market Category|Test Issue|Financial Status|Round Lot Size AAC|Australia Acquisition Corp. - Ordinary Shares|S|N|D|100 AACC|Asset Acceptance Capital Corp. - Common Stock|Q|N|N|100 AACOU|Australia Acquisition Corp.
Symbol|Security Name|Market Category|Test Issue|Financial Status|Round Lot Size
AAC|Australia Acquisition Corp. - Ordinary Shares|S|N|D|100
AACC|Asset Acceptance Capital Corp. - Common Stock|Q|N|N|100
AACOU|Australia Acquisition Corp. - Unit|S|N|N|100
AACOW|Australia Acquisition Corp. - Warrant|S|N|N|100
AAIT|iShares MSCI All Country Asia Information Technology Index Fund|G|N|N|100
AAME|Atlantic American Corporation - Common Stock|G|N|N|100
我阅读了以下数据:
data <- read.table("nasdaqlisted.txt", sep="|", quote='', header=TRUE, as.is=TRUE)
为什么会这样 我会咬一口,试着解释一下我对这些问题的理解 您不需要大型测试文件来演示该问题。一个简单的
data.frame
可以:
test <- data.frame(var1=1:2,var2=letters[1:2])
> test
var1 var2
1 1 a
2 2 b
如您所料,具有类似于列表的结构
> str(test)
'data.frame': 2 obs. of 2 variables:
$ var1: int 1 2
$ var2: Factor w/ 2 levels "a","b": 1 2
> str(as.list(test))
List of 2
$ var1: int [1:2] 1 2
$ var2: Factor w/ 2 levels "a","b": 1 2
当您针对data.frame
或list
指定matrix
调用时,您将得到一个填充了data.frame或list元素的矩阵
result1 <- matrix(test)
> result1
[,1]
[1,] Integer,2
[2,] factor,2
这意味着它现在既是一个矩阵
又是一个列表
> is.matrix(result1)
[1] TRUE
> is.list(result1)
[1] TRUE
如果从该对象中删除尺寸标注,它将不再是矩阵
,而将恢复为仅是列表
dim(result1) <- NULL
> result1
[[1]]
[1] 1 2
[[2]]
[1] a b
Levels: a b
> is.matrix(result1)
[1] FALSE
> is.list(result1)
[1] TRUE
> str(result1)
List of 2
$ : int [1:2] 1 2
$ : Factor w/ 2 levels "a","b": 1 2
dim(result1)result1
[[1]]
[1] 1 2
[[2]]
[1] a b
级别:a b
>is.矩阵(结果1)
[1] 假的
>is.list(结果1)
[1] 真的
>str(结果1)
2人名单
$:int[1:2]12
$:系数w/2“a”、“b”级:1 2
result1 <- matrix(test)
> result1
[,1]
[1,] Integer,2
[2,] factor,2
> str(result1)
List of 2
$ : int [1:2] 1 2
$ : Factor w/ 2 levels "a","b": 1 2
- attr(*, "dim")= int [1:2] 2 1
> is.matrix(result1)
[1] TRUE
> is.list(result1)
[1] TRUE
dim(result1) <- NULL
> result1
[[1]]
[1] 1 2
[[2]]
[1] a b
Levels: a b
> is.matrix(result1)
[1] FALSE
> is.list(result1)
[1] TRUE
> str(result1)
List of 2
$ : int [1:2] 1 2
$ : Factor w/ 2 levels "a","b": 1 2