Question

s <- "height (female), weight, BRCA1, height (female), BRCA1, weight, body mass index, body mass index, weight, weight, height (e.g. by kilos), body mass index." 

> unique(strsplit(s, ",")[[1]])
[1] "height (female)"         " weight"                 " BRCA1"                  " height (female)"        " body mass index"        " height (e.g. by kilos)"      " body mass index."

我有一个具有以下结构的字符串：<string>, <string>, <string>, ..., <string>.

除了最后一个之外，每个<string>都用逗号分隔，后跟一个句点。我想使用正则表达式删除重复的字符串。字符串可以采用以下三种格式之一：

后跟(...)的字词，例如height (female)或height (e.g. by kilos)
一个字：例如weight或BRCA1
由空格分隔的多个单词，例如body mass index

我想要的输出是：

"height (female), weight, BRCA1, body mass index, height (e.g. by kilos)."

简单地在逗号上执行strsplit不会考虑在height (female)第二次出现之前有空格的特殊情况，或者在最后body mass index之后出现空格的特殊情况一段时间。

Answer 1

@ thelatemail的评论你指出了正确的方向。使用unlist(strsplit(x = <input string>, split = <regex pattern>))拉出逗号和空格。 unique删除重复项，paste(<character vector>, collapse = ", ")将所有内容重新组合在一起。不要忘记unlist，或者唯一会查找列表中的不同元素而不是字符向量。

# input
s <- "height (female), weight, BRCA1, height (female), BRCA1, weight, body mass index, body mass index, weight, weight, height (e.g. by kilos), body mass index." 

# code
paste(unique(unlist(strsplit(s, ",\\s+|\\.$"))), collapse = ", ")
# [1] "height (female), weight, BRCA1, body mass index, height (e.g. by kilos)"

Answer 2

只要您不必在输入中转义任何逗号，并且格式已知（例如，字符串以应该被剥离的句点结束），这可以通过几个简单的步骤完成：

library(stringr)
s_unique = s %>%
    str_remove("\\.$") %>%
    str_split(",", simplify = TRUE) %>%
    str_trim() %>%  # Trim whitespace
    unique()

paste0(s_unique, collapse = ", ")

输出：

[1] "height (female), weight, BRCA1, body mass index, height (e.g. by kilos)"

正则表达式删除重复的字符串

2 个答案: