R语言 获取所有变量的类型

v09wglhw  于 11个月前  发布在  其他
关注(0)|答案(7)|浏览(133)

在R语言中,我想在脚本的末尾检索一个全局变量列表,并将其覆盖。

#declare a few sample variables
a<-10
b<-"Hello world"
c<-data.frame()

#get all global variables in script and iterate over them
myGlobals<-objects()
for(i in myGlobals){
  print(typeof(i))     #prints 'character'
}

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我的问题是typeof(i)总是返回character,即使变量ac不是字符变量。我如何才能在for循环中获得变量的原始类型?

0s0u357o

0s0u357o1#

您需要使用get来获取值,而不是ls返回的对象的字符名称:

x <- 1L
typeof(ls())
[1] "character"
typeof(get(ls()))
[1] "integer"

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或者,对于所呈现的问题,您可能希望使用eapply

eapply(.GlobalEnv,typeof)
$x
[1] "integer"

$a
[1] "double"

$b
[1] "character"

$c
[1] "list"

erhoui1w

erhoui1w2#

R/Rscript没有具体的数据库。

R解释器有一个duck类型的内存分配系统。没有内置的方法来告诉你指向内存的指针的数据类型。Duck类型是为了提高速度,但事实证明这是一个坏主意,因为现在这样的语句:print(is.integer(5))返回TRUE,is.integer(as.integer(5))返回TRUE。
关于基本类型的R手册:https://cran.r-project.org/doc/manuals/R-lang.html#Basic-types
你所能期望的最好的结果就是编写自己的函数来探测你的内存指针,然后使用消除过程来决定它是否适合你的需要。

如果你的变量是一个全局变量或对象:

您的object()需要用get(...)穿透,然后才能看到内部。示例:

a <- 10
myGlobals <- objects()
for(i in myGlobals){
  typeof(i)         #prints character
  typeof(get(i))    #prints integer
}

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typeof(...)探测变量指针到内存:

例如,R函数typeof有一个偏置,可以给予最大深度的类型。

library(tibble)

#expression              notes                                  type
#----------------------- -------------------------------------- ----------
typeof(TRUE)             #a single boolean:                     logical
typeof(1L)               #a single numeric with L postfixed:    integer
typeof("foobar")         #A single string in double quotes:     character
typeof(1)                #a single numeric:                     double
typeof(list(5,6,7))      #a list of numeric:                    list
typeof(2i)               #an imaginary number                   complex

typeof(5 + 5L)           #double + integer is coerced:          double
typeof(c())              #an empty vector has no type:          NULL
typeof(!5)               #a bang before a double:               logical
typeof(Inf)              #infinity has a type:                  double
typeof(c(5,6,7))         #a vector containing only doubles:     double
typeof(c(c(TRUE)))       #a vector of vector of logicals:       logical
typeof(matrix(1:10))     #a matrix of doubles has a type:       list

typeof(substr("abc",2,2))#a string at index 2 which is 'b' is:  character
typeof(c(5L,6L,7L))      #a vector containing only integers:    integer
typeof(c(NA,NA,NA))      #a vector containing only NA:          logical
typeof(data.frame())     #a data.frame with nothing in it:      list
typeof(data.frame(c(3))) #a data.frame with a double in it:     list
typeof(c("foobar"))      #a vector containing only strings:     character
typeof(pi)               #builtin expression for pi:            double

typeof(1.66)             #a single numeric with mantissa:       double
typeof(1.66L)            #a double with L postfixed             double
typeof(c("foobar"))      #a vector containing only strings:     character
typeof(c(5L, 6L))        #a vector containing only integers:    integer
typeof(c(1.5, 2.5))      #a vector containing only doubles:     double
typeof(c(1.5, 2.5))      #a vector containing only doubles:     double
typeof(c(TRUE, FALSE))   #a vector containing only logicals:    logical

typeof(factor())         #an empty factor has default type:     integer
typeof(factor(3.14))     #a factor containing doubles:          integer
typeof(factor(T, F))     #a factor containing logicals:         integer
typeof(Sys.Date())       #builtin R dates:                      double
typeof(hms::hms(3600))   #hour minute second timestamp          double
typeof(c(T, F))          #T and F are builtins:                 logical
typeof(1:10)             #a builtin sequence of numerics:       integer
typeof(NA)               #The builtin value not available:      logical

typeof(c(list(T)))       #a vector of lists of logical:         list
typeof(list(c(T)))       #a list of vectors of logical:         list
typeof(c(T, 3.14))       #a vector of logicals and doubles:     double
typeof(c(3.14, "foo"))   #a vector of doubles and characters:   character
typeof(c("foo",list(T))) #a vector of strings and lists:        list
typeof(list("foo",c(T))) #a list of strings and vectors:        list
typeof(TRUE + 5L)        #a logical plus an integer:            integer
typeof(c(TRUE, 5L)[1])   #The true is coerced to 1              integer
typeof(c(c(2i), TRUE)[1])#logical coerced to complex:           complex
typeof(c(NaN, 'batman')) #NaN's in a vector don't dominate:     character
typeof(5 && 4)           #doubles are coerced by order of &&    logical
typeof(8 < 'foobar')     #string and double is coerced          logical
typeof(list(4, T)[[1]])  #a list retains type at every index:   double
typeof(list(4, T)[[2]])  #a list retains type at every index:   logical
typeof(2 ** 5)           #result of exponentiation              double
typeof(0E0)              #exponential lol notation              double
typeof(0x3fade)          #hexidecimal                           double
typeof(paste(3, '3'))    #paste promotes types to string        character
typeof(3 + 四)           #R pukes on unicode                    error
typeof(iconv("a", "latin1", "UTF-8")) #UTF-8 characters         character
typeof(5 == 5)           #result of a comparison:               logical

class(...)探测变量指针到内存:

例如,Rx 1 e0f1x偏向于给予封装类型的容器或结构的类型。

library(tibble)

#expression            notes                                    class
#--------------------- ---------------------------------------- ---------
class(matrix(1:10))     #a matrix of doubles has a class:       matrix
class(factor("hi"))     #factor of items is:                    factor
class(TRUE)             #a single boolean:                      logical
class(1L)               #a single numeric with L postfixed:     integer
class("foobar")         #A single string in double quotes:      character
class(1)                #a single numeric:                      numeric
class(list(5,6,7))      #a list of numeric:                     list
class(2i)               #an imaginary                           complex
class(data.frame())     #a data.frame with nothing in it:       data.frame
class(Sys.Date())       #builtin R dates:                       Date
class(sapply)           #a function is                          function
class(charToRaw("hi"))  #convert string to raw:                 raw
class(array("hi"))      #array of items is:                     array

class(5 + 5L)           #double + integer is coerced:          numeric
class(c())              #an empty vector has no class:         NULL
class(!5)               #a bang before a double:               logical
class(Inf)              #infinity has a class:                 numeric
class(c(5,6,7))         #a vector containing only doubles:     numeric
class(c(c(TRUE)))       #a vector of vector of logicals:       logical

class(substr("abc",2,2))#a string at index 2 which is 'b' is:  character
class(c(5L,6L,7L))      #a vector containing only integers:    integer
class(c(NA,NA,NA))      #a vector containing only NA:          logical
class(data.frame(c(3))) #a data.frame with a double in it:     data.frame
class(c("foobar"))      #a vector containing only strings:     character
class(pi)               #builtin expression for pi:            numeric

class(1.66)             #a single numeric with mantissa:       numeric
class(1.66L)            #a double with L postfixed             numeric
class(c("foobar"))      #a vector containing only strings:     character
class(c(5L, 6L))        #a vector containing only integers:    integer
class(c(1.5, 2.5))      #a vector containing only doubles:     numeric
class(c(TRUE, FALSE))   #a vector containing only logicals:    logical

class(factor())       #an empty factor has default class:      factor
class(factor(3.14))   #a factor containing doubles:            factor
class(factor(T, F))   #a factor containing logicals:           factor
class(hms::hms(3600)) #hour minute second timestamp            hms difftime
class(c(T, F))        #T and F are builtins:                   logical
class(1:10)           #a builtin sequence of numerics:         integer
class(NA)             #The builtin value not available:        logical

class(c(list(T)))       #a vector of lists of logical:         list
class(list(c(T)))       #a list of vectors of logical:         list
class(c(T, 3.14))       #a vector of logicals and doubles:     numeric
class(c(3.14, "foo"))   #a vector of doubles and characters:   character
class(c("foo",list(T))) #a vector of strings and lists:        list
class(list("foo",c(T))) #a list of strings and vectors:        list
class(TRUE + 5L)        #a logical plus an integer:            integer
class(c(TRUE, 5L)[1])   #The true is coerced to 1              integer
class(c(c(2i), TRUE)[1])#logical coerced to complex:           complex
class(c(NaN, 'batman')) #NaN's in a vector don't dominate:     character
class(5 && 4)           #doubles are coerced by order of &&    logical
class(8 < 'foobar')     #string and double is coerced          logical
class(list(4, T)[[1]])  #a list retains class at every index:  numeric
class(list(4, T)[[2]])  #a list retains class at every index:  logical
class(2 ** 5)           #result of exponentiation              numeric
class(0E0)              #exponential lol notation              numeric
class(0x3fade)          #hexidecimal                           numeric
class(paste(3, '3'))     #paste promotes class to string       character
class(3 + 四)           #R pukes on unicode                   error
class(iconv("a", "latin1", "UTF-8")) #UTF-8 characters         character
class(5 == 5)           #result of a comparison:               logical

获取变量的数据storage.mode

当一个R变量被写入磁盘时,数据布局再次改变,称为data's storage.mode。函数storage.mode(...)揭示了这一低级信息:参见Mode, Class, and Type of R objects。你不需要担心R的storage.mode,除非你试图理解在向磁盘分配和从磁盘阅读数据时发生的往返转换/转换所导致的延迟。

Demo:R/Rscript gettype(your_variable)

运行这段R代码,然后根据你的目的调整它,它会很好地猜测它是什么类型。

get_type <- function(variable){ 
  sz <- as.integer(length(variable)) #length of your variable 
  tof <- typeof(variable)            #typeof your variable 
  cls <- class(variable)             #class of your variable 
  isc <- is.character(variable)      #what is.character() has to say about it.  
  d <- dim(variable)                 #dimensions of your variable 
  isv <- is.vector(variable) 
  if (is.matrix(variable)){  
    d <- dim(t(variable))             #dimensions of your matrix
  }    
  #observations ----> datatype 
  if (sz>=1 && tof == "logical" && cls == "logical" && isv == TRUE){ return("vector of logical") } 
  if (sz>=1 && tof == "integer" && cls == "integer" ){ return("vector of integer") } 
  if (sz==1 && tof == "double"  && cls == "Date" ){ return("Date") } 
  if (sz>=1 && tof == "raw"     && cls == "raw" ){ return("vector of raw") } 
  if (sz>=1 && tof == "double"  && cls == "numeric" ){ return("vector of double") } 
  if (sz>=1 && tof == "double"  && cls == "array" ){ return("vector of array of double") } 
  if (sz>=1 && tof == "character"  && cls == "array" ){ return("vector of array of character") } 
  if (sz>=0 && tof == "list"       && cls == "data.frame" ){ return("data.frame") } 
  if (sz>=1 && isc == TRUE         && isv == TRUE){ return("vector of character") } 
  if (sz>=1 && tof == "complex"    && cls == "complex" ){ return("vector of complex") } 
  if (sz==0 && tof == "NULL"       && cls == "NULL" ){ return("NULL") } 
  if (sz>=0 && tof == "integer"    && cls == "factor" ){ return("factor") } 
  if (sz>=1 && tof == "double"     && cls == "numeric" && isv == TRUE){ return("vector of double") } 
  if (sz>=1 && tof == "double"     && cls == "matrix"){ return("matrix of double") } 
  if (sz>=1 && tof == "character"  && cls == "matrix"){ return("matrix of character") } 
  if (sz>=1 && tof == "list"       && cls == "list" && isv == TRUE){ return("vector of list") } 
  if (sz>=1 && tof == "closure"    && cls == "function" && isv == FALSE){ return("closure/function") } 
  return("it's pointer to memory, bruh") 
} 
assert <- function(a, b){ 
  if (a == b){ 
    cat("P") 
  } 
  else{ 
    cat("\nFAIL!!!  Sniff test:\n") 
    sz <- as.integer(length(variable))   #length of your variable 
    tof <- typeof(variable)              #typeof your variable 
    cls <- class(variable)               #class of your variable 
    isc <- is.character(variable)        #what is.character() has to say about it. 
    d <- dim(variable)                   #dimensions of your variable 
    isv <- is.vector(variable) 
    if (is.matrix(variable)){  
      d <- dim(t(variable))                   #dimensions of your variable 
    } 
    if (!is.function(variable)){ 
      print(paste("value: '", variable, "'")) 
    } 
    print(paste("get_type said: '", a, "'")) 
    print(paste("supposed to be: '", b, "'")) 
 
    cat("\nYour pointer to memory has properties:\n")  
    print(paste("sz: '", sz, "'")) 
    print(paste("tof: '", tof, "'")) 
    print(paste("cls: '", cls, "'")) 
    print(paste("d: '", d, "'")) 
    print(paste("isc: '", isc, "'")) 
    print(paste("isv: '", isv, "'")) 
    quit() 
  } 
}
#these asserts give a sample for exercising the code. 
assert(get_type(TRUE),      "vector of logical")  #everything is a vector in R by default. 
assert(get_type(c(TRUE)),   "vector of logical")  #c() just casts to vector 
assert(get_type(c(c(TRUE))),"vector of logical")  #casting vector multiple times does nothing 
assert(get_type(!5),        "vector of logical")  #bang inflicts 'not truth-like' 
assert(get_type(1L),              "vector of integer")   #naked integers are still vectors of 1 
assert(get_type(c(1L, 2L)),       "vector of integer")   #Longs are not doubles 
assert(get_type(c(1L, c(2L, 3L))),"vector of integer")   #nested vectors of integers 
assert(get_type(c(1L, c(TRUE))),  "vector of integer")   #logicals coerced to integer 
assert(get_type(c(FALSE, c(1L))), "vector of integer")   #logicals coerced to integer 
assert(get_type("foobar"),        "vector of character")    #character here means 'string' 
assert(get_type(c(1L, "foobar")), "vector of character")    #integers are coerced to string 
assert(get_type(5),           "vector of double") 
assert(get_type(5 + 5L),      "vector of double") 
assert(get_type(Inf),         "vector of double") 
assert(get_type(c(5,6,7)),    "vector of double") 
assert(get_type(NaN),           "vector of double") 
assert(get_type(list(5)),       "vector of list")    #your list is in a vector. 
assert(get_type(list(5,6,7)),   "vector of list") 
assert(get_type(c(list(5,6,7))),"vector of list") 
assert(get_type(list(c(5,6),T)),"vector of list")    #vector of list of vector and logical 
assert(get_type(list(5,6,7)),   "vector of list") 
assert(get_type(2i),            "vector of complex") 
assert(get_type(c(2i, 3i, 4i)), "vector of complex") 
assert(get_type(c()),            "NULL") 
assert(get_type(data.frame()),   "data.frame") 
assert(get_type(data.frame(4,5)),"data.frame") 
assert(get_type(Sys.Date()),     "Date") 
assert(get_type(sapply),         "closure/function") 
assert(get_type(charToRaw("hi")),"vector of raw") 
assert(get_type(c(charToRaw("a"), charToRaw("b"))), "vector of raw") 
assert(get_type(array(4)),       "vector of array of double") 
assert(get_type(array(4,5)),     "vector of array of double") 
assert(get_type(array("hi")),    "vector of array of character") 
assert(get_type(factor()),       "factor") 
assert(get_type(factor(3.14)),   "factor") 
assert(get_type(factor(TRUE)),   "factor") 
assert(get_type(matrix(3,4,5)),  "matrix of double") 
assert(get_type(as.matrix(5)),   "matrix of double") 
assert(get_type(matrix("yatta")),"matrix of character")


我在这里引入了C++/Java/Python的思想,让我了解了内存的最大值是什么。R triad类型系统就像试图将意大利面条钉在墙上,<-<<-会在你最不怀疑的时候将你的矩阵打包成一个列表。正如古老的鸭子类型谚语所说:如果它像鸭子一样摇摆,如果它像鸭子一样嘎嘎叫,如果它有羽毛,那么它就是鸭子。

nx7onnlm

nx7onnlm3#

你可以使用class(x)来检查变量类型。如果要求检查 Dataframe 的所有变量类型,那么可以使用sapply(x,class)。

svmlkihl

svmlkihl4#

> mtcars %>% 
+     summarise_all(typeof) %>% 
+     gather
    key  value
1   mpg double
2   cyl double
3  disp double
4    hp double
5  drat double
6    wt double
7  qsec double
8    vs double
9    am double
10 gear double
11 carb double

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我尝试了classtypeof函数,但都失败了。

slsn1g29

slsn1g295#

设计来做你想要的基本上相反的事情,这是我的工具箱玩具之一:

lstype<-function(type='closure'){
inlist<-ls(.GlobalEnv)
if (type=='function') type <-'closure'
typelist<-sapply(sapply(inlist,get),typeof)
return(names(typelist[typelist==type]))
}

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zvokhttg

zvokhttg6#

lapply(your_frame,class)提供类似于以下内容的内容:
$tikr [1]“factor”
$Date [1]“日期”
$Open [1]“numeric”
$High [1]“numeric”
等等

tktrz96b

tktrz96b7#

> dataframe %>% 
+     summarise_all(typeof) %>% 
+     gather

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我不能评论前面的答案,然而,这是我发现的最好的快捷方式.为了执行上面的代码,请确保您有包“dupir”或“magrittr”或“tidyverse”与“tidyr”一起安装沿着,并启动相应的库.

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