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R语言数据结构之列表_r将字符串改为列表

作者：小蓝xlanll | 2024-06-11 09:42:34

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r将字符串改为列表

1.创建列表


# 向量元素类型必须一致，按优先级自动转换
data1 <-c(66,'student',TRUE)
data1

## [1] "66" "student" "TRUE"


#列表元素类型可能不同
data2 <-list(66,'student',TRUE)
data2

## [[1]]
## [1] 66

## [[2]]
## [1] "student"

## [[3]]
## [1] TRUE

str()：可以紧凑的显示对象内部结构

str(data2)

## List of 3
## $ : num 66
## $ : chr "student"
## $ : logi TRUE


a <- 1:5
b <- c('one', 'two', 'three')
c <- matrix(1:20, 4, 5)
mylist <- list(a, b, c)
mylist

## [[1]]
## [1] 1 2 3 4 5

## [[2]]
## [1] "one" "two" "three"

## [[3]]
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

str(mylist)

## List of 3
## $ : int [1:5] 1 2 3 4 5
## $ : chr [1:3] "one" "two" "three"
## $ : int [1:4, 1:5] 1 2 3 4 5 6 7 8 9 10 ...


# 给列表元素添加名称
mylist <- list(first=a, second=b, third=c)
mylist

## $first
## [1] 1 2 3 4 5

## $second
## [1] "one" "two" "three"

## $third
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

str(mylist)

## List of 3
## $ first : int [1:5] 1 2 3 4 5
## $ second: chr [1:3] "one" "two" "three"
## $ third : int [1:4, 1:5] 1 2 3 4 5 6 7 8 9 10 ...

2.访问列表


# 长度信息
length(mylist)

## [1] 3


# 名称信息
names(mylist)

## [1] "first" "second" "third"


# 返回值为列表
mylist[1]

## $first
## [1] 1 2 3 4 5

mylist[2]

## $second
## [1] "one" "two" "three"

mylist[3]

## $third
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

class()：查看数据结构


#class(mylist[1])
#class(mylist[2])
class(mylist[3])

## [1] "list"

mylist['first']

## [1] 1 2 3 4 5

mylist['second']

## $second
## [1] "one" "two" "three"

mylist['third']

## $third
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

class(mylist['third'])

## [1] "list"


# 返回值为元素本身类型
mylist[[1]]

## [1] 1 2 3 4 5

mylist[[2]]

## [1] "one" "two" "three"

mylist[[3]]

## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

class(mylist[[1]])

## [1] "integer"

class(mylist[[2]])

## [1] "character"

matrix类型：矩阵类型

array类型：N维数组

class(mylist[[3]])

## [1] "matrix" "array"


# 返回值为元素本身类型
mylist[['first']]

## [1] 1 2 3 4 5

class(mylist[['first']])

## [1] "integer"


# 返回值为元素本身类型
mylist$first

## [1] 1 2 3 4 5

class(mylist$first)

## [1] "integer"


# 访问多个元素
# mylist(1, 3) #注意:写法有误
# mylist[1, 3] #注意:写法有误
# mylist[[1, 3]] #注意:写法有误
mylist[c(1, 3)]

## $first
## [1] 1 2 3 4 5

## $third
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

mylist[c('first', 'third')]

## $first
## [1] 1 2 3 4 5

## $third
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

mylist[c(TRUE, FALSE, TRUE)]

## $first
## [1] 1 2 3 4 5

## $third
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

3.修改列表

(1)增加元素


mylist[4] <- 'This is a list'
mylist['fourth'] <- 34
mylist$fifth <- FALSE
mylist

## $first
## [1] 1 2 3 4 5

## $second
## [1] "one" "two" "three"

## $third
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

## [[4]]
## [1] "This is a list"

## $fourth
## [1] 34

## $fifth
## [1] FALSE

(2)修改元素


mylist[4] <- 8888
mylist['fourth'] <- TRUE
mylist$fifth <- 'Student'
mylist

## $first
## [1] 1 2 3 4 5

## $second
## [1] "one" "two" "three"

## $third
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

## [[4]]
## [1] 8888

## $fourth
## [1] TRUE

## $fifth
## [1] "Student"

(3)删除元素


mylist <- mylist[-4]
mylist

## $first
## [1] 1 2 3 4 5

## $second
## [1] "one" "two" "three"

## $third
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20

## $fourth
## [1] TRUE

## $fifth
## [1] "Student"


mylist <- mylist[c(-4, -5)]
mylist

## $first
## [1] 1 2 3 4 5

## $second
## [1] "one" "two" "three"

## $third
## [,1] [,2] [,3] [,4] [,5]
## [1,] 1 5 9 13 17
## [2,] 2 6 10 14 18
## [3,] 3 7 11 15 19
## [4,] 4 8 12 16 20


mylist[3] <- NULL
mylist

## $first
## [1] 1 2 3 4 5

## $second
## [1] "one" "two" "three"

4.合并列表


yourlist <- list(1:3, 'school')
yourlist

## [[1]]
## [1] 1 2 3

## [[2]]
## [1] "school"

mylist

## $first
## [1] 1 2 3 4 5

## $second
## [1] "one" "two" "three"


lst <- c(mylist, yourlist)
lst

## $first
## [1] 1 2 3 4 5

## $second
## [1] "one" "two" "three"

## [[3]]
## [1] 1 2 3

## [[4]]
## [1] "school"

class(lst)

## [1] "list"

5.列表转化为向量

mylist

## $first
## [1] 1 2 3 4 5

## $second
## [1] "one" "two" "three"

unlist()：将list结构的数据，变成非list的数据，即将list数据变成字符串向量或者数字向量的形式。

unlist(mylist)

## first1 first2 first3 first4 first5 second1 second2 second3
## "1" "2" "3" "4" "5" "one" "two" "three"

lst

## $first
## [1] 1 2 3 4 5

## $second
## [1] "one" "two" "three"

## [[3]]
## [1] 1 2 3

## [[4]]
## [1] "school"

unlist(lst)

## first1 first2 first3 first4 first5 second1 second2 second3
## "1" "2" "3" "4" "5" "one" "two" "three" "1"
##
## "2" "3" "school"

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