编辑：如何在 R 中的特定字符值之间插入 NA

Question

我有一个带有虚拟字符 "break" 的值列表，编码为表示换行符：

 [11] "break"       "-9.737715"   "0.000091"   "-0.000340"   "-0.001318"
 [16] "-38.103233"  "-10.327046"  "break"      "27.469583"   "break"

我需要：1) 计算每次出现 "break" 之间的字符数，以及 2) 将 NA 插入不符合指定字符数 (= 9) 的字符串中。例如，我上面代码的理想输出是：

         [11] "break"       "-9.737715"   "0.000091"   "-0.000340"   "-0.001318"
         [16] "-38.103233"  "-10.327046"  "NA"         "NA"          "NA"
         [21] "break"       "27.469583"   "NA"         "NA"          "NA"   
         [26] "NA"          "NA"          "NA"         "NA"          "NA"
         [31]  "break"

无法在任何地方找到解决方案...感谢帮助！

Answer 1

这几乎您要问的是 - 它在最后一次休息后添加了一组 NA。（如果你知道最后一个条目是中断，那么你可以在计算中断之前将其删除。如果最后一个条目不是中断，它应该有效。）

x <-  c("break" ,"-9.737715", "0.000091", "-0.000340", "-0.001318", "-38.103233",  "-10.327046",  "break" , "27.469583",   "break")
count_breaks = cumsum(x == "break")
unlist(tapply(x, count_breaks, function(.x) {
  c(.x, rep(NA, 10 - length(.x)))
}))

Answer 2

其中一种方法可能是

y <- c()
cnt_betwn_break <- 0

for(i in 1:length(a)){
  ifelse(a[i]=='break',
         {if(!(cnt_betwn_break %in% c(0,9))) y <- c(y, rep(NA, 9 - cnt_betwn_break))
          cnt_betwn_break <- 0},
         cnt_betwn_break <- cnt_betwn_break + 1)
  y <- c(y, a[i])
}
y
# [1] "break"      "-9.737715"  "0.000091"   "-0.000340"  "-0.001318"  "-38.103233" "-10.327046" NA          
# [9] NA           NA           "break"      "27.469583"  NA           NA           NA           NA          
#[17] NA           NA           NA           NA           "break"

示例数据：

a <- c("break", "-9.737715", "0.000091", "-0.000340", "-0.001318", "-38.103233", "-10.327046", "break", "27.469583", "break")

编辑：如何在 R 中的特定字符值之间插入 NA

EDITED: How to insert NAs between specific character values in R

r

data-manipulation

data-management