Question

在Mac OS X - [R 2.13.1我试图导入具有用于千个分离器和逗号作为小数点的点的数据文件，以及尾随减去负值。

基本上，我正在尝试转换：

"A|324,80|1.324,80|35,80-"

到

  V1    V2     V3    V4
1  A 324.80 1324.8 -35.80

现在，交互式地进行以下工作：

gsub("\\.","","1.324,80")
[1] "1324,80"

gsub("(.+)-$","-\\1", "35,80-")
[1] "-35,80"

并将它们组合在一起：

gsub("\\.", "", gsub("(.+)-$","-\\1","1.324,80-"))
[1] "-1324,80"

但是，我无法从read.data中删除千位分隔符：

setClass("num.with.commas")

setAs("character", "num.with.commas", function(from) as.numeric(gsub("\\.", "", sub("(.+)-$","-\\1",from))) )
mydata <- "A|324,80|1.324,80|35,80-"

mytable <- read.table(textConnection(mydata), header=FALSE, quote="", comment.char="", sep="|", dec=",", skip=0, fill=FALSE,strip.white=TRUE, colClasses=c("character","num.with.commas", "num.with.commas", "num.with.commas"))

Warning messages:
1: In asMethod(object) : NAs introduced by coercion
2: In asMethod(object) : NAs introduced by coercion
3: In asMethod(object) : NAs introduced by coercion

mytable
  V1 V2 V3 V4
1  A NA NA NA

请注意，如果我从“\\”更改。对于“，”在函数中，事情看起来有点不同：

setAs("character", "num.with.commas", function(from) as.numeric(gsub(",", "", sub("(.+)-$","-\\1",from))) )

mytable <- read.table(textConnection(mydata), header=FALSE, quote="", comment.char="", sep="|", dec=",", skip=0, fill=FALSE,strip.white=TRUE, colClasses=c("character","num.with.commas", "num.with.commas", "num.with.commas"))

mytable
  V1    V2     V3    V4
1  A 32480 1.3248 -3580

我认为问题是read.data with dec =“，”将传入的“，”转换为“。”在调用（来自“num.with.commas”）之前，输入字符串可以是例如“1.324.80”。

我想为（ “1.123,80 - ”， “num.with.commas”）返回-1123.80和作为（ “1.100.123,80”， “num.with.commas”）返回1100123.80 <。 / p>

如何让我的num.with.commas替换输入字符串中除最后小数点以外的所有？

更新：首先，我添加了负面预测，并在控制台中使用as（）：

setAs("character", "num.with.commas", function(from) as.numeric(gsub("(?!\\.\\d\\d$)\\.", "", gsub("(.+)-$","-\\1",from), perl=TRUE)) ) as("1.210.123.80-","num.with.commas") [1] -1210124 as("10.123.80-","num.with.commas") [1] -10123.8 as("10.123.80","num.with.commas") [1] 10123.8

但是，read.table仍然存在同样的问题。在我的函数中添加一些print（）s表明num.with.commas实际上得到了逗号，而不是重点。

所以我目前的解决方案是从“，”更换为“。”在num.with.commas。

setAs("character", "num.with.commas", function(from) as.numeric(gsub(",","\\.",gsub("(?!\\.\\d\\d$)\\.", "", gsub("(.+)-$","-\\1",from), perl=TRUE))) ) mytable <- read.table(textConnection(mydata), header=FALSE, quote="", comment.char="", sep="|", dec=",", skip=0, fill=FALSE,strip.white=TRUE, colClasses=c("character","num.with.commas", "num.with.commas", "num.with.commas")) mytable V1 V2 V3 V4 1 A 324.8 1101325 -35.8

Answer 1

您应首先删除所有句点，然后在强制使用as.numeric（）之前将逗号更改为小数点。您可以稍后控制如何使用选项打印小数点（OutDec =“，”）。我不认为R在内部使用逗号作为小数分隔符，即使在传统的语言环境中也是如此。

> tst <- c("A","324,80","1.324,80","35,80-")
> 
> as.numeric( sub("\\,", ".", sub("(.+)-$","-\\1", gsub("\\.", "", tst)) ) )
[1]     NA  324.8 1324.8  -35.8
Warning message:
NAs introduced by coercion

Answer 2

这是一个包含正则表达式和替换的解决方案

mydata <- "A|324,80|1.324,80|35,80-"
# Split data
mydata2 <- strsplit(mydata,"|",fixed=TRUE)[[1]]
# Remove commas
mydata3 <- gsub(",","",mydata2,fixed=TRUE)
# Move negatives to front of string
mydata4 <- gsub("^(.+)-$","-\\1",mydata3)
# Convert to numeric
mydata.cleaned <- c(mydata4[1],as.numeric(mydata4[2:4]))

导入包含逗号，千位分隔符和尾随减号的CSV数据

2 个答案: