Question

在以下字符串中：

"I may opt for a yam for Amy, May, and Tommy."

如何删除非字母字符并将所有字母转换为小写字母并对R中每个字母内的字母进行排序？

与此同时，我尝试对句子中的单词进行排序并删除重复项。

Answer 1

您可以使用stringi

library(stringi)
unique(stri_sort(stri_trans_tolower(stri_extract_all_words(txt, simplify = TRUE))))

给出了：

## [1] "a"     "amy"   "and"   "for"   "i"     "may"   "opt"   "tommy" "yam"

<强>更新

正如@DavidArenburg所提到的，我忽略了“将字母中的字母排序”作为问题的一部分。您没有提供所需的输出，也没有立即应用程序，但是，假设您想要识别哪些单词具有匹配的对应项（字符串距离为0）：

unique(stri_sort(stri_trans_tolower(stri_extract_all_words(txt, simplify = TRUE)))) %>%
  stringdistmatrix(., ., useNames = "strings", method = "qgram") %>%

#       a amy and for i may opt tommy yam
# a     0   2   2   4 2   2   4     6   2
# amy   2   0   4   6 4   0   6     4   0
# and   2   4   0   6 4   4   6     8   4
# for   4   6   6   0 4   6   4     6   6
# i     2   4   4   4 0   4   4     6   4
# may   2   0   4   6 4   0   6     4   0
# opt   4   6   6   4 4   6   0     4   6
# tommy 6   4   8   6 6   4   4     0   4
# yam   2   0   4   6 4   0   6     4   0

  apply(., 1, function(x) sum(x == 0, na.rm=TRUE)) 

# a   amy   and   for     i   may   opt tommy   yam 
# 1     3     1     1     1     3     1     1     3

每行0多个"amy", "may", "yam"的字词有加扰对应字词。

Answer 2

str <- "I may opt for a yam for Amy, May, and Tommy."

## Clean the words (just keep letters and convert to lowercase)
words <- strsplit(tolower(gsub("[^A-Za-z ]", "", str)), " ")[[1]]

## split the words into characters and sort them
sortedWords <- sapply(words, function(word) sort(unlist(strsplit(word, ""))))

## Join the sorted letters back together
sapply(sortedWords, paste, collapse="")

# i     may     opt     for       a     yam     for     amy     may     and 
# "i"   "amy"   "opt"   "for"     "a"   "amy"   "for"   "amy"   "amy"   "adn" 
# tommy 
# "mmoty" 

## If you want to convert result back to string
do.call(paste, lapply(sortedWords, paste, collapse=""))
# [1] "i amy opt for a amy for amy amy adn mmoty"

Answer 3

stringr将让您处理R和C-speed中的所有字符集，而magrittr将允许您使用适合您需求的管道习语：

library(stringr)
library(magrittr)

txt <- "I may opt for a yam for Amy, May, and Tommy."

txt %>% 
  str_to_lower %>%                                            # lowercase
  str_replace_all("[[:punct:][:digit:][:cntrl:]]", "") %>%    # only alpha
  str_replace_all("[[:space:]]+", " ") %>%                    # single spaces
  str_split(" ") %>%                                          # tokenize
  extract2(1) %>%                                             # str_split returns a list
  sort %>%                                                    # sort
  unique                                                      # unique words

  ## [1] "a"     "amy"   "and"   "for"   "i"     "may"   "opt"   "tommy" "yam"

Answer 4

我维护的 qdap 包具有适用于此的bag_o_words函数：

txt <- "I may opt for a yam for Amy, May, and Tommy."

library(qdap)

unique(sort(bag_o_words(txt)))

## [1] "a"     "amy"   "and"   "for"   "i"     "may"   "opt"   "tommy" "yam"

如何删除非字母字符并将所有字母转换为R中的小写？

4 个答案: