Question

我有这个字符串：

235072,testing,some252f4,14084-things224072,and,other2524,14084-thingies223552,testing,some/2wr24,14084-things

我想用6位数字分割字符串。即 - 我想要这个：

235072,testing,some2wg2f4,wf484-things
224072,and,other25wg4,14-thingies
223552,testing,some/2wr24,14084-things

如何使用正则表达式执行此操作？以下内容不起作用（使用stringr包）：

> blahblah <- "235072,testing,some252f4,14084-things224072,and,other2524,14084-thingies223552,testing,some/2wr24,14084-things"
> test <- str_split(blahblah, "([0-9]{6}.*)")
> test
[[1]]
[1] "" ""

我错过了什么？

Answer 1

这是一种方法，基础R使用正向前瞻和后视，并感谢@thelatemail进行更正：

strsplit(x, "(?<=.)(?=[0-9]{6})", perl = TRUE)[[1]]
# [1] "235072,testing,some252f4,14084-things"  
# [2] "224072,and,other2524,14084-thingies"    
# [3] "223552,testing,some/2wr24,14084-things"

Answer 2

使用str_extract_all的替代方法。注意我已使用.*?进行'非贪婪'匹配，否则.*会扩展以抓取所有内容：

> str_extract_all(blahblah, "[0-9]{6}.*?(?=[0-9]{6}|$)")[[1]]
[1] "235072,testing,some252f4,14084-things"  "224072,and,other2524,14084-thingies"    "223552,testing,some/2wr24,14084-things"

Answer 3

一种易于理解的方法是添加标记，然后分割这些标记的位置。这样做的优点是只能查找6位数的序列，并且不需要周围文本中的任何其他功能，其功能可能会随着您添加新的和未发布的数据而改变。

library(stringr)
library(magrittr)

str <- "235072,testing,some252f4,14084-things224072,and,other2524,14084-thingies223552,testing,some/2wr24,14084-things"

out <- 
    str_replace_all(str, "(\\d{6})", "#SPLIT_HERE#\\1") %>% 
    str_split("#SPLIT_HERE#") %>% 
    unlist

[1] ""                                       "235072,testing,some252f4,14084-things" 
[3] "224072,and,other2524,14084-thingies"    "223552,testing,some/2wr24,14084-things"

如果您的匹配发生在字符串的开头或结尾，str_split()将在结果向量中插入空白字符条目以指示（如上所述）。如果您不需要该信息，可以使用out[nchar(out) != 0]轻松删除该信息。

[1] "235072,testing,some252f4,14084-things"  "224072,and,other2524,14084-thingies"   
[3] "223552,testing,some/2wr24,14084-things"

Answer 4

With less complex regex, you can do as following:

s <- "235072,testing,some252f4,14084-things224072,and,other2524,14084-thingies223552,testing,some/2wr24,14084-things"
l <- str_locate_all(string = s, "[0-9]{6}")
str_sub(string = s, start = as.data.frame(l)$start, 
    end = c(tail(as.data.frame(l)$start, -1) - 1, nchar(s)) )
# [1] "235072,testing,some252f4,14084-things"
# [2] "224072,and,other2524,14084-thingies"
# [3] "223552,testing,some/2wr24,14084-things"

如何在R中使用str_split和regex？

4 个答案: