本文介绍了R 中的简化 dput()的处理方法,对大家解决问题具有一定的参考价值,需要的朋友们下面随着小编来一起学习吧!

问题描述

我错过了一种以透明方式将数据添加到 SO 答案的方法.我的经验是,来自 dput()structure 对象有时会使没有经验的用户感到不必要的困惑.但是,我没有耐心每次都将其复制/粘贴到一个简单的数据框中,并希望将其自动化.类似于 dput() 的东西,但在简化版本中.

I miss a way to add data to an SO answer in a transparent manner. My experience is that the structure object from dput() at times confuses inexperienced users unnecessary. I do however not have the patience to copy/paste it into a simple data frame each time and would like to automate it. Something similar to dput(), but in a simplified version.

说我通过复制/粘贴和其他一些房东有这样的数据,

Say I by copy/pasting and some other hos have data like this,

Df <- data.frame(A = c(2, 2, 2, 6, 7, 8),
                 B = c("A", "G", "N", NA, "L", "L"),
                 C = c(1L, 3L, 5L, NA, NA, NA))

看起来像这样,

Df
#>   A    B  C
#> 1 2    A  1
#> 2 2    G  3
#> 3 2    N  5
#> 4 6 <NA> NA
#> 5 7    L NA
#> 6 8    L NA

在一个整数、一个因子和一个数值向量内,

Within one integer, one factor and one numeric vector,

str(Df)
#> 'data.frame':    6 obs. of  3 variables:
#>  $ A: num  2 2 2 6 7 8
#>  $ B: Factor w/ 4 levels "A","G","L","N": 1 2 4 NA 3 3
#>  $ C: int  1 3 5 NA NA NA

现在,我想在 SO 上分享这个,但我并不总是拥有它来自的 原始 数据框.我通常以 SO 形式 pipe() 它,而我知道的唯一方法是 dput().喜欢,

Now, I would like to share this on SO, but I do not always have the orginal data frame it came from. More often than not I pipe() it in form SO and the only way I know to get it out is dput(). Like,

dput(Df)
#> structure(list(A = c(2, 2, 2, 6, 7, 8), B = structure(c(1L, 2L, 
#> 4L, NA, 3L, 3L), .Label = c("A", "G", "L", "N"), class = "factor"), 
#> C = c(1L, 3L, 5L, NA, NA, NA)), .Names = c("A", "B", "C"), row.names = c(NA, 
#> -6L), class = "data.frame")

但是,正如我在顶部所说,这些 structure 看起来很混乱.出于这个原因,我正在寻找一种以某种方式压缩 dput() 输出的方法.我想像这样的输出,

but, as I said at the top, these structures can look quite confusing. For that reason I am looking for a way to compress dput()'s output in some way. I imagine an output that looks something like this,

dput_small(Df)
#> data.frame(A = c(2, 2, 2, 6, 7, 8), B = c("A", "G", "N", NA, "L", "L"),
#> C = c(1L, 3L, 5L, NA, NA, NA))

这可能吗?我意识到还有其他类,例如 liststbltbl_df 等.

Is that possible? I realize there's other classes, like lists, tbl, tbl_df, etc.

推荐答案

  • dput 的包装器(处理标准 data.framestibbleslists)

  • a wrapper around dput (handles standard data.frames, tibbles and lists)

read.table 解决方案(用于data.frames)

一个tibble::tribble解决方案(对于data.frames,返回一个tibble)

a tibble::tribble solution (for data.frames, returning a tibble)

全部包含 nrandom 参数,它们允许仅输入数据的头部或动态采样.

All include n and random parameter which allow one to dput only the head of the data or sample it on the fly.

dput_small1(Df)
# Df <- data.frame(
#   A = c(2, 2, 2, 6, 7, 8),
#   B = structure(c(1L, 2L, 4L, NA, 3L, 3L), .Label = c("A", "G", "L", 
#     "N"), class = "factor"),
#   C = c(1L, 3L, 5L, NA, NA, NA) ,
#   stringsAsFactors=FALSE)

dput_small2(Df,stringsAsFactors=TRUE)
# Df <- read.table(sep="	", text="
#   A   B   C
#   2   A    1
#   2   G    3
#   2   N    5
#   6   NA  NA
#   7   L   NA
#   8   L   NA", header=TRUE, stringsAsFactors=TRUE)

dput_small3(Df)
# Df <- tibble::tribble(
#   ~A, ~B, ~C,
#   2,           "A",          1L,
#   2,           "G",          3L,
#   2,           "N",          5L,
#   6, NA_character_, NA_integer_,
#   7,           "L", NA_integer_,
#   8,           "L", NA_integer_
# )
# Df$B <- factor(Df$B)

包装 dput

此选项提供的输出非常接近问题中提出的输出.它非常通用,因为它实际上包裹在 dput 周围,但单独应用于列.

Wrapper around dput

This option that gives an output very close to the one proposed in the question. It's quite general because it's actually wrapped around dput, but applied separately on columns.

multiline 表示'keep dput's default output layout into multiple lines'.

dput_small1<- function(x,
                       name=as.character(substitute(x)),
                       multiline = TRUE,
                       n=if ('list' %in% class(x)) length(x) else nrow(x),
                       random=FALSE,
                       seed = 1){
  name
  if('tbl_df' %in% class(x)) create_fun <- "tibble::tibble" else
    if('list' %in% class(x)) create_fun <- "list" else
      if('data.table' %in% class(x)) create_fun <- "data.table::data.table" else
        create_fun <- "data.frame"
    
    if(random) {
      set.seed(seed)
      if(create_fun == "list") x <- x[sample(1:length(x),n)] else 
        x <- x[sample(1:nrow(x),n),]
    } else {
      x <- head(x,n)
    }
    
    line_sep <- if (multiline) "
    " else ""
    cat(sep='',name," <- ",create_fun,"(
  ",
        paste0(unlist(
          Map(function(item,nm) paste0(nm,if(nm=="") "" else " = ",paste(capture.output(dput(item)),collapse=line_sep)),
              x,if(is.null(names(x))) rep("",length(x)) else names(x))),
          collapse=",
  "),
        if(create_fun == "data.frame") ",
  stringsAsFactors = FALSE)" else "
)")
}

dput_small1(list(1,2,c=3,d=4),"my_list",random=TRUE,n=3)
# my_list <- list(
#   2,
#   d = 4,
#   c = 3
# )

read.table解决方案

对于 data.frames,我觉得以更明确/表格格式的输入很舒服.

read.table solution

For data.frames I find it comfortable however to have the input in a more explicit/tabular format.

这可以使用 read.table 来实现,然后自动重新格式化 read.table 无法正确设置的列类型.不像第一个解决方案那样通用,但在 SO 上发现的 95% 的情况下都能顺利工作.

This can be reached using read.table, then reformatting automatically the type of columns that read.table wouldn't get right. Not as general as first solution but will work smoothly for 95% of the cases found on SO.

dput_small2 <- function(df,
                        name=as.character(substitute(df)),
                        sep='	',
                        header=TRUE,
                        stringsAsFactors = FALSE,
                        n= nrow(df),
                        random=FALSE,
                        seed = 1){
    name
    if(random) {
      set.seed(seed)
      df <- df[sample(1:nrow(df),n),]
    } else {
      df <- head(df,n)
    }
  cat(sep='',name,' <- read.table(sep="',sub('	','\\t',sep),'", text="
  ',
      paste(colnames(df),collapse=sep))
  df <- head(df,n)
  apply(df,1,function(x) cat(sep='','
  ',paste(x,collapse=sep)))
  cat(sep='','", header=',header,', stringsAsFactors=',stringsAsFactors,')')
  
  sapply(names(df), function(x){
    if(is.character(df[[x]]) & suppressWarnings(identical(as.character(as.numeric(df[[x]])),df[[x]]))){ # if it's a character column containing numbers
      cat(sep='','
',name,'$',x,' <- as.character(', name,'$',x,')')
    } else if(is.factor(df[[x]]) & !stringsAsFactors) { # if it's a factor and conversion is not automated
      cat(sep='','
',name,'$',x,' <- factor(', name,'$',x,')')
    } else if(inherits(df[[x]], "POSIXct")){
      cat(sep='','
',name,'$',x,' <- as.POSIXct(', name,'$',x,')')
    } else if(inherits(df[[x]], "Date")){
      cat(sep='','
',name,'$',x,' <- as.Date(', name,'$',x,')')
    }})
  invisible(NULL)
}

最简单的情况

dput_small2(iris,n=6)

将打印:

iris <- read.table(sep="	", text="
  Sepal.Length  Sepal.Width Petal.Length    Petal.Width Species
  5.1   3.5 1.4 0.2  setosa
  4.9   3.0 1.4 0.2  setosa
  4.7   3.2 1.3 0.2  setosa
  4.6   3.1 1.5 0.2  setosa
  5.0   3.6 1.4 0.2  setosa
  5.4   3.9 1.7 0.4  setosa", header=TRUE, stringsAsFactors=FALSE)

执行时又会返回:

#   Sepal.Length Sepal.Width Petal.Length Petal.Width Species
# 1          5.1         3.5          1.4         0.2  setosa
# 2          4.9         3.0          1.4         0.2  setosa
# 3          4.7         3.2          1.3         0.2  setosa
# 4          4.6         3.1          1.5         0.2  setosa
# 5          5.0         3.6          1.4         0.2  setosa
# 6          5.4         3.9          1.7         0.4  setosa

str(iris)
# 'data.frame': 6 obs. of  5 variables:
# $ Sepal.Length: num  5.1 4.9 4.7 4.6 5 5.4
# $ Sepal.Width : num  3.5 3 3.2 3.1 3.6 3.9
# $ Petal.Length: num  1.4 1.4 1.3 1.5 1.4 1.7
# $ Petal.Width : num  0.2 0.2 0.2 0.2 0.2 0.4
# $ Species     : chr  " setosa" " setosa" " setosa" " setosa" ...

更复杂

虚拟数据:

test <- data.frame(a=1:5,
                   b=as.character(6:10),
                   c=letters[1:5],
                   d=factor(letters[6:10]),
                   e=Sys.time()+(1:5),
                   stringsAsFactors = FALSE)

这个:

dput_small2(test,'df2')

将打印:

df2 <- read.table(sep="	", text="
  a b   c   d   e
  1 6   a   f   2018-02-15 11:53:17
  2 7   b   g   2018-02-15 11:53:18
  3 8   c   h   2018-02-15 11:53:19
  4 9   d   i   2018-02-15 11:53:20
  5 10  e   j   2018-02-15 11:53:21", header=TRUE, stringsAsFactors=FALSE)
df2$b <- as.character(df2$b)
df2$d <- factor(df2$d)
df2$e <- as.POSIXct(df2$e)

执行时又会返回:

#   a  b c d                   e
# 1 1  6 a f 2018-02-15 11:53:17
# 2 2  7 b g 2018-02-15 11:53:18
# 3 3  8 c h 2018-02-15 11:53:19
# 4 4  9 d i 2018-02-15 11:53:20
# 5 5 10 e j 2018-02-15 11:53:21

str(df2)    
# 'data.frame': 5 obs. of  5 variables:
# $ a: int  1 2 3 4 5
# $ b: chr  "6" "7" "8" "9" ...
# $ c: chr  "a" "b" "c" "d" ...
# $ d: Factor w/ 5 levels "f","g","h","i",..: 1 2 3 4 5
# $ e: POSIXct, format: "2018-02-15 11:53:17" "2018-02-15 11:53:18" "2018-02-15 11:53:19" "2018-02-15 11:53:20" ...

all.equal(df2,test)
# [1] "Component "e": Mean absolute difference: 0.4574251" # only some rounding error

tribble解决方案

read.table 选项可读性很强,但不是很通用.tribble 几乎可以处理任何数据类型(尽管因素需要临时修复).

tribble solution

The read.table option is very readable but not very general. with tribble pretty much any data type can be handled (though factors need adhoc fixing).

此解决方案对于 OP 的示例不是很有用,但对于列表列非常有用(请参见下面的示例).要使用输出,需要库 tibble.

This solution isn't so useful for OP's example but is great for list columns (see example below). To make use of the output, library tibble is required.

就像我的第一个解决方案一样,它是 dput 的包装器,但不是dputting"列,而是dputting"元素.

Just as my first solution, it's a wrapper around dput, but instead of 'dputting' columns, i'm 'dputting' elements.

dput_small3 <- function(df,
                        name=as.character(substitute(df)),
                        n= nrow(df),
                        random=FALSE,
                        seed = 1){
  name
  if(random) {
    set.seed(seed)
    df <- df[sample(1:nrow(df),n),]
  } else {
    df <- head(df,n)
  }
  df1 <- lapply(df,function(col) if(is.factor(col)) as.character(col) else col)
  dputs   <- sapply(df1,function(col){
    col_dputs <- sapply(col,function(elt) paste(capture.output(dput(elt)),collapse=""))
    max_char <- max(nchar(unlist(col_dputs)))
    sapply(col_dputs,function(elt) paste(c(rep(" ",max_char-nchar(elt)),elt),collapse=""))
  })
  lines   <- paste(apply(dputs,1,paste,collapse=", "),collapse=",
  ")
  output  <- paste0(name," <- tibble::tribble(
  ",
                    paste0("~",names(df),collapse=", "),
                    ",
  ",lines,"
)")
  cat(output)
  sapply(names(df), function(x) if(is.factor(df[[x]])) cat(sep='','
',name,'$',x,' <- factor(', name,'$',x,')'))
  invisible(NULL)
}

dput_small3(dplyr::starwars[c(1:3,11)],"sw",n=6,random=TRUE)
# sw <- tibble::tribble(
#   ~name, ~height, ~mass, ~films,
#   "Lando Calrissian", 177L,       79,                     c("Return of the Jedi", "The Empire Strikes Back"),
#      "Finis Valorum", 170L, NA_real_,                                                   "The Phantom Menace",
#       "Ki-Adi-Mundi", 198L,       82, c("Attack of the Clones", "The Phantom Menace", "Revenge of the Sith"),
#           "Grievous", 216L,      159,                                                  "Revenge of the Sith",
#     "Wedge Antilles", 170L,       77,       c("Return of the Jedi", "The Empire Strikes Back", "A New Hope"),
#         "Wat Tambor", 193L,       48,                                                 "Attack of the Clones"
# )

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10-12 11:22