条件gsub替换

Question

我有文本数据(以R)，并希望用数据帧中的其他字符替换一些字符。我认为这将是一个简单的任务，使用空格上的str拆分，并创建一个向量，然后我可以使用匹配(%in%)，然后可以粘贴回一起。但后来我想到了标点符号。句子的最后一个词和结尾的标点符号之间没有空格。

我想，可能有一种更简单的方法来实现我想要的东西，而不是成为我的代码的复杂混乱。我想知道这个问题的方向。

#Character String
x <- "I like 346 ice cream cones.  They're 99 percent good!  I ate 46."

#Replacement Values Dataframe
  symbol text                     
1 "346"  "three hundred forty six"
2 "99"   "ninety nine"            
3 "46"   "forty six" 

#replacement dataframe
numDF <- 
data.frame(symbol = c("346","99", "46"),
           text = c("three hundred forty six", "ninety nine","forty six"),
           stringsAsFactors = FALSE)

期望的结果：

[1] "I like three hundred forty six ice cream cones.  They're ninety nine percent good!  You ate forty six?")

编辑:我最初的标题是这个有条件的gsub，因为这在我看来是什么样子，即使不涉及gsub。

Answer 1

也许这是由乔希·奥布赖恩的回答所启发的，是吗？

x <- "I like 346 ice cream cones.  They're 99 percent good!  I ate 46."
numDF <- structure(c("346", "99", "46", "three hundred forty six", "ninety nine", 
"forty six"), .Dim = c(3L, 2L), .Dimnames = list(c("1", "2", 
"3"), c("symbol", "text")))

pat <-  paste(numDF[,"symbol"], collapse="|")
repeat {
    m <- regexpr(pat, x)
    if(m==-1) break
    sym <- regmatches(x,m)
    regmatches(x,m) <- numDF[match(sym, numDF[,"symbol"]), "text"]
}
x

Answer 2

此解决方案在同名包中使用gsubfn：

library(gsubfn)

(pat <-  paste(numDF$symbol, collapse="|"))
# [1] "346|99|46"

gsubfn(pattern = pat,
       replacement = function(x) {
           numDF$text[match(x, numDF$symbol)]
       },
       x)
[1] "I like three hundred forty six ice cream cones.  They're ninety nine percent good!  I ate forty six."

Answer 3

您可以在空格或单词边界上拆分(这将在单词和标点符号之间匹配)：

> x
[1] "I like 346 ice cream cones.  They're 99 percent good!  I ate 46."
> strsplit(x, split='\\s|\\>|\\<')
[[1]]
 [1] "I"       "like"    "346"     "ice"     "cream"   "cones"   "."      
 [8] ""        "They"    "'re"     "99"      "percent" "good"    "!"      
[15] ""        "I"       "ate"     "46"      "."      

然后你就可以做你的替代品了。