Question

如果该列具有＆＃34; ClearPrevious＆＃34;，我想删除整行及其上面的行。但是我有多顺序＆＃34; ClearPrevious＆＃34;这让事情变得有点复杂。

输入：

 tmp <- data.frame(V1 = c("event1", "ClearPrevious", "event2", "event3", "event4", "ClearPrevious", "ClearPrevious", "event5"))

我的输出：

1 event2
2 event3
3 event5

期望的输出：

1 event2
2 event5

我的尝试失败代码：

row_delete <- c(which(tmp$V1 == "ClearPrevious"))
row_to_be_deleted <- c(row_delete-1)
View(tmp[-c(row_to_be_deleted, row_delete),])

Answer 1

这是我试过的：

rm(list=ls())
tmp <- data.frame(V1 = c("event1", "ClearPrevious", "event2", "event3", 
                         "event4", "ClearPrevious", "ClearPrevious", "event5"),
                  stringsAsFactors = F)

while(any(grep('ClearPrevious', tmp$V1)))
{
  clearindex <- which(tmp$V1 == 'ClearPrevious')
  event_index <- grep('event', tmp$V1)
  toremove <- intersect(clearindex-1, event_index)

  V1 <- tmp[-c(toremove, toremove+1),]
  tmp <- as.data.frame(V1)

}
tmp
# event2
# event5

Answer 2

一种方法：

mutate(tmp,m=`length<-`(V1[-1],nrow(tmp)))%>%
     with(V1[(!m=="ClearPrevious"|is.na(m))&!V1=="ClearPrevious"])
[1] event2 event3 event5

fun=function(s) {
  while(any(grepl("ClearPrevious",s)))
    s=trimws(gsub("\\w+\\s+ClearPrevious","",paste(s,collapse = " ")))
  strsplit(s,"\\s+")[[1]]
}
fun(tmp$V1)
[1] "event2" "event5"

有条件地删除具有多个引用的行

2 个答案: