用模式替换R中的字符串，并替换两个向量

假设我有两个向量，如下所示：

a <- c("this", "is", "test")
b <- c("that", "was", "boy")

---

a如果您愿意使用非基本包，
stringi
将在这里非常有效：

stringi::stri_replace_all_fixed(string, a, b, vectorize_all = FALSE)
#[1] "that was a story about a boy"

请注意，对于长度大于1的输入字符串，这种方法也同样适用

为了安全起见，您可以调整此选项（类似于RUser的答案），以在替换之前检查单词边界：

stri_replace_all_regex(string, paste0("\\b", a, "\\b"), b, vectorize_all = FALSE)

例如，这将确保您不会意外地将
his
替换为
hwas
。
以下是一些解决方案。即使
string
是字符串的字符向量，在这种情况下，将对字符串的每个组成部分进行替换，它们都将工作

> library(stringi)
> stri_replace_all_regex(string, "\\b" %s+% a %s+% "\\b", b, vectorize_all=FALSE)
#[1] "that was a story about a boy"

1）减少这不使用包

Reduce(function(x, i) gsub(paste0("\\b", a[i], "\\b"), b[i], x), seq_along(a), string)
## [1] "that was a story about a boy"

2）gsubfn
gsubfn
类似于
gsub
，但替换参数可以是替换（或某些其他对象）的列表

3）循环这不是矢量化的，而是为了比较而添加的。没有使用任何软件包

out <- string
for(i in seq_along(a)) out <- gsub(paste0("\\b", a[i], "\\b"), b[i], out)
out
## [1] "that was a story about a boy"

out插入一个仅依赖于
R base的小功能
：

repWords <- function(string,toRep,Rep,sep='\\s'){

  wrds <- unlist(strsplit(string,sep))
  ix <- match(toRep,wrds)
  wrds[ix] <- Rep  
  return(paste0(wrds,collapse = ' '))

}

a <- c("this", "is", "test")
b <- c("that", "was", "boy")

string <- "this is a story about a test"

> repWords(string,a,b)
[1] "that was a story about a boy"

repWords谈到外部软件包，这里还有一个：

a <- c("this", "is", "test")
b <- c("that", "was", "boy")
x <- "this is a story about a test"


library(qdap)
mgsub(a,b,x)

美好的我还没有接触到减少。非常感谢。我添加了一个关于cyclesAlso
regmatches（string，gregexpr（粘贴（a，collapse=“|”）的注释，string））@G.Grothendieck-我也说过类似的话。当然，它也需要
\\b
来指定单词边界，就像
gsub
解决方案一样。@LateMail，它更长更复杂，它覆盖输入并修复它，使其工作方式类似于（2）正则表达式比（2）中的复杂得多。它的优点是不使用任何包。很好
mgsub
可以让生活看起来更轻松一些如果
a
out <- string
for(i in seq_along(a)) out <- gsub(paste0("\\b", a[i], "\\b"), b[i], out)
out
## [1] "that was a story about a boy"

a <- c("a", "A")
b <- rev(a)

# swap "a" and "A"
a <- c("a", "A")
b <- rev(a)

tmp <- gsubfn("\\w+", setNames(as.list(seq_along(a)), a), string)
gsubfn("\\w+", setNames(as.list(b), seq_along(a)), tmp)
## [1] "this is A story about A test"

repWords <- function(string,toRep,Rep,sep='\\s'){

  wrds <- unlist(strsplit(string,sep))
  ix <- match(toRep,wrds)
  wrds[ix] <- Rep  
  return(paste0(wrds,collapse = ' '))

}

a <- c("this", "is", "test")
b <- c("that", "was", "boy")

string <- "this is a story about a test"

> repWords(string,a,b)
[1] "that was a story about a boy"

a <- c("this", "is", "test")
b <- c("that", "was", "boy")
x <- "this is a story about a test"


library(qdap)
mgsub(a,b,x)

 "that was a story about a boy"