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r - 文本的 R 特征提取

问题描述

我的问题是关于文本挖掘和文本处理的。

我想从我的文本中构建一个数据框。

我的数据是：

text <- c("#*TeX: The Program,
#@Donald E. Knuth,
#t1986,
#c,
#index68,
""
#*Foundations of Databases.,
#@Serge Abiteboul,Richard Hull,Victor Vianu,
#t1995,
#c,
#index69,
#%1118192,
#%189,
#%1088975,
#%971271,
#%832272,
#!From the Book: This book will teach you how to write specifications of computer systems, using the language TLA+.")

我的预期输出是：

expected <- data.frame(title=c("#*TeX: The Program", "#*Foundations of Databases."), authors=c("#@Donald E. Knuth", "#@Serge Abiteboul,Richard Hull,Victor Vianu"), year=c("#t1986", "#t1995"), revue=c("#c", "#c"), id_paper=c("#index68", "#index69"),
                       id_ref=c(NA,"#%1118192, #%189, #%1088975, #%971271, #%832272"), abstract=c(NA, "#!From the Book: This book will teach you how to write specifications of computer systems, using the language TLA+."))

我的代码是：

coln <- c("title", "authors", "year", "revue","id_paper", "id_ref", "abstract")
      title_index <- grep("^#[*]", text)
      authors_index <- grep("#@", text)
      year_index <- grep("#t", text)
      revue_index <- grep("#c", text)
      id_paper_index <- grep("#index", text)
      id_refindex <- grep("#%", text)
      abstract_index <- grep("#!", text)
      df <- matrix(NA, nrow=length(title_index), ncol=length(coln))
      colnames(df) <- coln
      stoc_index <- grep("#cSTOC", text)
      sigir_index <- grep("#cSIGIR", text)}


  ########## titre
  {der_pos <- length(title_index)
    tit_position  <- c(title_index , der_pos)
    for(i in 1:length(title_position)){
      if(i != length(title_position)){
        df[i, "title"] <- text[title_position[i]]
      }
    }
  }

  ########## author 
{der_pos <- length(authors_index)
    authors_position  <- c(authors_index )
    for(i in 1:length(auteur_position)){
      if(i != length(auteur_position)){
        df[i, "auteur"] <- text[auteur_position[i]]
      }
    }
  }

  ########## year
{der_pos <- length(year_index)
    year_position  <- c(year_index , der_pos)
    for(i in 1:length(year_position)){
      if(i != length(year_position)){
        df[i, "année"] <- text[year_position[i]]
      }
    }
  }

  ##########??? revue
  {der_pos <- length(revue_index)
    revue_position  <- c(revue_index )
    for(i in 1:length(revue_position)){
      if(i != length(revue_position)){
        df[i, "revue"] <- text[revue_position[i]]
      }
    }
  }

  ########## id_paper
  {der_pos <- length(id_paper_index)
    id_paper_position  <- c(id_paper_index , dern_pos)
    for(i in 1:length(id_paper_position)){
      if(i != length(id_paper_position)){
        df[i, "id_paper"] <- text[id_paper_position[i]]
      }
    }
  }

  ########## id_ref
  {der_pos <- length(id_ref_index)
    id_ref_position  <- c(id_ref_index , der_pos)
    for(i in 1:length(id_ref_position)){
      if(i != length(id_ref_position)){
        df[i, "id_ref"] <- text[id_ref_position[i]]
      }
    }
  }
  ########## abstract
  {der_pos <- length(abstract_index)
    abstract_position  <- c(abstract_index , der_pos)
    for(i in 1:length(abstract_position)){
      if(i != length(abstract_position)){
        df[i, "abstract"] <- text[abstract_position[i]]
      }
    }
  }

所以我想在一行中提取参考

如果您有解决方案在一篇文章中以逗号分隔的一列中连接多个引用，请提前感谢您。

谢谢 ：）

标签： rtextnlptext-miningfeature-extraction

解决方案

新的和改进的

text.n <- strsplit(text, "\n(?=#\\*)", perl=TRUE)[[1]]; text.n

text.s <- lapply(text.n, function(x) strsplit(x, "\n")[[1]])

patterns <- list(title="^#\\*", 
                autors="^#@",
                  year="^#t",
                 revue="^#c",
              id_paper="^#index",
                id_ref="^#%",
              abstract="^#!")

tex.l <- lapply(text.s, function(x)
  lapply(patterns, function(y)
    paste(sub(y, "", grep(y, x, value=TRUE)), collapse=",")
  )
) 

tex.m <- matrix(unlist(tex.l), ncol=length(tex.l[[1]]), byrow=TRUE)
tex.df <- as.data.frame(tex.m, stringsAsFactors=FALSE)
colnames(tex.df) <- names(patterns)

str(tex.df)

# 'data.frame': 2 obs. of  7 variables:
# $ title   : chr "TeX: The Program" "Foundations of Databases."
# $ autors  : chr "Donald E. Knuth" "Serge Abiteboul,Richard Hull,Victor Vianu"
# $ year    : chr "1986" "1995"
# $ revue   : chr "" ""
# $ id_paper: chr "68" "69"
# $ id_ref  : chr "" "1118192,189,1088975,971271,832272"
# $ abstract: chr "" "From the Book: This book will teach you how to write 
#                     specifications of computer systems, using the language TLA+."

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