基于几种模式重新排序 R 向量

如何解决基于几种模式重新排序 R 向量

vec <- c("a: 25","g: 32","h: 44","i: 88","","a: 22","i: 53a","h: 4.2","g: rt","a: zzz","h: 53","g: 634","i: 4","qq\t5.6","a: p","h: r","i: 6","g: 6","")
beg_pattern <- "a: "; end_element <- ""
grep_pattern1 <- "g: "; grep_pattern2 <- "h: "
desired_reordered_vec <- c("a: 25","")

本质上，我想重新排序我的向量，以便在以 beg_pattern 开始并以 end_element 结尾的每个元素块中，我的“g”​​元素出现在我的“h”元素之前。在这个例子中有不止一个有效的解向量。在我的实际数据中，模式是不同的，除了结束元素，每个块会有 20-200 个元素。我的问题包含以下三个问题的元素：How to split vector into list based on consecutive unique values、Split a vector into chunks、Split a vector into three vectors of unequal length in R。但我还没有能够拼凑出一个解决方案。我可以通过这种方式获取我的索引：

a <- grep("a: ",vec); z <- which("" == vec)
u <- grep("g: ",vec); v <- grep("h: ",vec)

但我不确定其中哪些（如果有）将帮助我执行所需的重新排序。

解决方法

您可以在 Base R 中编写一个函数来执行此操作：

my_sort <- function(x){
  y <- grep('^(g|h):',x)
  x[y] <- x[y][match(sub(":.*","",x[y]),c("g","h"))]
  x
}


f <- head(cumsum(vec == ''),-1)
ave(vec,c(f[1],f),FUN = my_sort)
 [1] "a: 25"  "g: 32"  "h: 44"  "i: 88"  ""       "a: 22"  "i: 53a" "g: rt"  "h: 4.2" ""       "a: zzz"
[12] "g: 634" "h: 53"  "i: 4"   "qq\t5.6" ""       "a: p"   "g: 6"   "i: 6"   "h: r"   ""