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mr.T
Asked:2020-03-04 22:48:33 +0000 UTC2020-03-04 22:48:33 +0000 UTC

R中的单词大小写

  • 772

有一个带有单词的向量

 # текст
text <- c("R is a very essential tool for data analysis. While it 
          is regarded as domain specific, it is a very complete programming 
          language. Almost certainly, many people who would benefit from
          using R, do not use it")
# разбиваю текст на вектор сo словами с пом. пакета stringr
text <- unlist(    stringr::str_match_all(text , '\\w+\\b')   )



 text
 [1] "R"           "is"          "a"           "very"        "essential"   "tool"        "for"        
 [8] "data"        "analysis"    "While"       "it"          "is"          "regarded"    "as"         
[15] "domain"      "specific"    "it"          "is"          "a"           "very"        "complete"   
[22] "programming" "language"    "Almost"      "certainly"   "many"        "people"      "who"        
[29] "would"       "benefit"     "from"        "using"       "R"           "do"          "not"        
[36] "use"         "it"

我想在其中找到“使用”一词

text[text=="using"]
[1] "using"

一切都很好，一切都被找到了，但是如果你稍微改变一下寄存器

text[text=="Using"]
character(0)

找不到这个词

问题是如何使单词搜索不区分大小写？

r

2 个回答

  1. 将向量中的单词转换为相同的寄存器就足够了：

    text <- tolower(text)
    • 5
  2. Best Answer

    您可以使用该功能grep

    grep("Using",text,ignore.case=TRUE,value=TRUE)

    ignore.case=TRUE- 忽略大小写

    value=TRUE- 返回向量的值，而不是找到的单词的位置

    更新程序

    grep将寻找条目。因此，搜索“it”将返回一个不完全正确的结果：

    grep("it",text,ignore.case=TRUE,value=T,useBytes = T)

    [1] “它” “它” “有益” “它”

    在这种情况下，函数会regexpr更好地工作：

    match<-regexpr("IT$",text,ignore.case=TRUE)
text[match==1]

    [1] “它” “它” “它”

    • 5

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