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regex - 从R中数据框中的文本字符串中删除正则表达式

问题描述

我有一个包含 1000 行的数据集，其中的文本包含灯的订单描述。数据中充满了不一致的正则表达式模式，在参考了几个解决方案后，我得到了一些帮助，但并没有解决问题。 R删除数据框中的多个文本字符串 从文本向量r中删除多个模式

我想删除所有分隔符，并且只保留 wordstoreplace 向量中存在的单词。

我尝试使用 lapply 删除分隔符并发布我创建了 2 个向量 - “wordstoremove”和“wordstoreplace”

我正在尝试应用“str_remove_all()”和“str_replace_all()”。第一个功能有效，但第二个无效。

最初我尝试使用一种非常幼稚的方法，但它太笨拙了。

mydata_sample=data.frame(x=c("LAMP, FLUORESCENT;TYPE TUBE LIGHT, POWER 8 W, POTENTIAL 230 V, COLORWHITE, BASE G5, LENGTH 302.5 MM; P/N: 37755,Mnfr:SuryaREF:  MODEL: FW/T5/33 GE 1/25,",
                        "LAMP, INCANDESCENT;TYPE HALOGEN, POWER 1 KW, POTENTIAL 230 V, COLORWHITE, BASE R7S; Make: Surya",
                        "BALLAST, LAMP; TYPE: ELECTROMAGNETIC, LAMP TYPE: TUBELIGHT/FLUORESCENT, POWER: 36/40 W, POTENTIAL: 240VAC 50HZ; LEGACY NO:22038  Make :Havells , Cat Ref No : LHB7904025",
                        "SWITCH,ELECTRICAL,TYPE:1 WCR   WAY,VOLTAGE:230V,CURRENT RATED:10A,NUMBEROFPOLES:1P,ADDITIONAL INFORMATION:FOR SNAPMODULESWITCH",
                 "Brief Desc:HIGH PRES. SODIUM VAPOUR LAMP 250W/400WDetailed Desc:Purchase order text :Short Description :HIGH PRES. SODIUM VAPOURLAMP 250W/400W===============================Part No :SON-T 250W/400W===============================Additional Specification :HIGH PRESSURE SODIUM VAPOUR LAMPSON-T 250W/400W USED  IN SURFACE INS SYSTEM TOP LIGHT"))

delimiters1=c('"',"\r\n",'-','=',';')
delimiters2=c('*',',',':')

library(dplyr)
library(stringr)
dat <- mydata_sample %>%   
  mutate(x1 = str_remove_all(x1, regex(str_c("\\b",delimiters1, "\\b", collapse = '|'), ignore_case = T)))

dat <- mydata_sample %>%   
  mutate(x1 = str_remove_all(x1, regex(str_c("\\b",delimiters2, "\\b", collapse = '|'), ignore_case = T)))
####Error in stri_replace_all_regex(string, pattern, fix_replacement(replacement),  : 
  Syntax error in regexp pattern. (U_REGEX_RULE_SYNTAX)

wordstoremove=c('Mnfr','MNFR',"VAPOURTYPEHIGH",'LHZZ07133099MNFR',"BJHF","BJOS",
                "BGEMF","BJIR","LIGHTING","FFT","FOR","ACCOMMODATIONQUANTITY","Cat",
                "Ref","No","Type","TYPE","QUANTITY","P/N")

wordstoreplace=c('HAVELLS','Havells','Bajaj','BAJAJGrade A','PHILIPS',
                 'Philips',"MAKEBAJAJ/CG","philips","Philips/Grade A/Grade A/CG/GEPurchase","CG","Bajaj",
                 "BAJAJ")

dat1 <- dat%>%   
  mutate(x1 = str_remove_all(x1, regex(str_c("\\b",wordstoremove, "\\b", collapse = '|'), ignore_case = T)))

dat1=dat1 %>%
  mutate(x1=str_replace_all(x1, wordstoreplace, 'Grade A'),ignore_case = T)
###Warning message:
In stri_replace_all_regex(string, pattern, fix_replacement(replacement),  :
  longer object length is not a multiple of shorter object length

标签： regexstringdplyrstringr

解决方案

正则表达式失败，因为您需要转义所有特殊字符。在此处查看差异：

# orig delimiters1=c('"', "\r\n", '-', '=', ';')
delimiters1=c('\\"', "\r\n", '-', '\\=', ';')

# orig delimiters2=c('*', ',', ':')
delimiters2=c('\\*', ',', '\\:')

对于您，str_replace_all()您需要单词是由 ​​a 分隔的单个字符串，|而不是 12 的向量

wordstoreplace <-
  c('HAVELLS','Havells','Bajaj','BAJAJGrade A','PHILIPS',
    'Philips',"MAKEBAJAJ/CG","philips","Philips/Grade A/Grade A/CG/GEPurchase","CG","Bajaj",
    "BAJAJ") %>% 
  paste0(collapse = "|")
# "HAVELLS|Havells|Bajaj|BAJAJGrade A|PHILIPS|Philips|MAKEBAJAJ/CG|philips|Philips/Grade A/Grade A/CG/GEPurchase|CG|Bajaj|BAJAJ"

然后运行而不会引发错误

dat1 <-
  dat %>%
  mutate(
    x1 = 
      str_remove_all(x1, regex(str_c("\\b", wordstoremove, "\\b", collapse = "|"), ignore_case = T)),
    x1 = str_replace_all(x1, wordstoreplace, "Grade A")
  )

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