从文件中读取特定的,模式匹配的行

Question

我有一个制表符分隔的文件,包含多个表格,每个表格都以标题为首,例如"Azuay \n","Bolivar \n","Cotopaxi \n"等,每个表格用两个换行符分隔.在R中,我如何读取该文件并仅选择对应于例如"Bolivar"的表(即指定的行),同时忽略对应于"Cotopaxi"的下表和上面对应于"Azuay"的表.

NB.我宁愿不在R外面修改表格.

数据看起来像这样.该文件以制表符分隔.

 Azuay
 region begin       stop
 1A     2017761     148749885
 1A     148863885   150111299
 1A     150329391   150346152
 1A     150432847   247191037


 Bolivar
 region begin           stop 
 2A     2785            242068364
 2A     736640          198339289


 Cotopaxi
 region begin           stop 
 4A     2282            9951846
 4A     11672561        11906166

Answer 1

这似乎做了这个工作:

read.entry.table <- function(file, entry) {

   lines <- readLines(file)

   table.entry <- lines == entry
   if (sum(table.entry) != 1) stop(paste(entry, "not found"))

   empty.lines <- which(lines == "")
   empty.lines <- c(empty.lines, length(lines) + 1L)

   table.start <- which(table.entry) + 1L
   table.end   <- empty.lines[which(empty.lines > table.start)[1]] - 1L

   return(read.table(textConnection(lines[seq(from = table.start,
                                              to   = table.end)]),
                     header = TRUE))
}

read.entry.table("test.txt", "Bolivar")
#   region  begin      stop
# 1     2A   2785 242068364
# 2     2A 736640 198339289

read.entry.table("test.txt", "Cotopaxi")
#   region    begin     stop
# 1     4A     2282  9951846
# 2     4A 11672561 11906166