R - 如何从多个匹配项中替换字符串(在数据框中)

Question

我需要用存储在数据帧中的一些匹配项替换字符串的子集。

例如 -

input_string = "Whats your name and Where're you from"

我需要从数据框中替换此字符串的一部分。说数据框是

matching <- data.frame(from_word=c("Whats your name", "name", "fro"),
            to_word=c("what is your name","names","froth"))

预期输出为 你叫什么名字，你来自哪里

笔记 -

它是匹配最大的字符串。在本例中，姓名 与 不匹配姓名 ，因为 name 是更大匹配的一部分

它必须匹配整个字符串而不是部分字符串。 “from” 的 fro 不应与“froth”匹配

我引用了下面的链接，但不知何故无法按预期/描述的方式完成这项工作

Match and replace multiple strings in a vector of text without looping in R

这是我在这里的第一篇文章。如果我没有提供足够的细节，请让我知道

Answer 1

编辑

根据 Sri 评论的输入，我建议使用:

library(gsubfn)
# words to be replaced
a <-c("Whats your","Whats your name", "name", "fro")
# their replacements
b <- c("What is yours","what is your name","names","froth")
# named list as an input for gsubfn
replacements <- setNames(as.list(b), a)
# the test string
input_string = "fro Whats your name and Where're name you from to and fro I Whats your"
# match entire words
gsubfn(paste(paste0("\\w*", names(replacements), "\\w*"), collapse = "|"), replacements, input_string)

原来的

我不会说这比您的简单循环更容易阅读，但它可能会更好地处理重叠替换:

# define the sample dataset
input_string = "Whats your name and Where're you from"
matching <- data.frame(from_word=c("Whats your name", "name", "fro", "Where're", "Whats"),
                       to_word=c("what is your name","names","froth", "where are", "Whatsup"))

# load used library
library(gsubfn)

# make sure data is of class character
matching$from_word <- as.character(matching$from_word)
matching$to_word <- as.character(matching$to_word)

# extract the words in the sentence
test <- unlist(str_split(input_string, " "))
# find where individual words from sentence match with the list of replaceble words
test2 <- sapply(paste0("\\b", test, "\\b"), grepl, matching$from_word)
# change rownames to see what is the format of output from the above sapply
rownames(test2) <- matching$from_word
# reorder the data so that largest replacement blocks are at the top
test3 <- test2[order(rowSums(test2), decreasing = TRUE),]
# where the word is already being replaced by larger chunk, do not replace again
test3[apply(test3, 2, cumsum) > 1] <- FALSE

# define the actual pairs of replacement
replacements <- setNames(as.list(as.character(matching[,2])[order(rowSums(test2), decreasing = TRUE)][rowSums(test3) >= 1]),
                         as.character(matching[,1])[order(rowSums(test2), decreasing = TRUE)][rowSums(test3) >= 1])

# perform the replacement
gsubfn(paste(as.character(matching[,1])[order(rowSums(test2), decreasing = TRUE)][rowSums(test3) >= 1], collapse = "|"),
       replacements,input_string)