3 种解决方案：
-
dput 的包装器（处理标准 data.frames、tibbles 和 lists）
-
read.table 解决方案（用于data.frames）
-
tibble::tribble 解决方案（对于data.frames，返回tibble）
所有都包含n 和random 参数，它们允许仅输入数据的头部或动态采样。
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="\t", 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。它很笼统，因为它实际上包裹在 dput 周围，但在列上单独应用。
multiline 表示'保持 dput 的默认输出布局成多行'。
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) "\n " else ""
cat(sep='',name," <- ",create_fun,"(\n ",
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=",\n "),
if(create_fun == "data.frame") ",\n stringsAsFactors = FALSE)" else "\n)")
}
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/表格格式输入很舒服。
这可以使用read.table 来实现，然后自动重新格式化read.table 无法正确处理的列类型。不像第一个解决方案那样通用，但对于SO 上发现的 95% 的案例都可以顺利工作。
dput_small2 <- function(df,
name=as.character(substitute(df)),
sep='\t',
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','\\\\t',sep),'", text="\n ',
paste(colnames(df),collapse=sep))
df <- head(df,n)
apply(df,1,function(x) cat(sep='','\n ',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='','\n',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='','\n',name,'$',x,' <- factor(', name,'$',x,')')
} else if(inherits(df[[x]], "POSIXct")){
cat(sep='','\n',name,'$',x,' <- as.POSIXct(', name,'$',x,')')
} else if(inherits(df[[x]], "Date")){
cat(sep='','\n',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="\t", 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="\t", 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）。
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。
就像我的第一个解决方案一样，它是 dput 的包装器，但我不是“dputting”列，而是“dputting”元素。
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=",\n ")
output <- paste0(name," <- tibble::tribble(\n ",
paste0("~",names(df),collapse=", "),
",\n ",lines,"\n)")
cat(output)
sapply(names(df), function(x) if(is.factor(df[[x]])) cat(sep='','\n',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"
# )