使用具有多个条件的ifelse编程R.

Question

你帮帮我了

我有data.frame E有四列我只使用R中的基本包我不使用for循环我有milion行

phone<-c(123,123,123,333,333,333,456,456,456,789,789,789,500,500,500,....etc) time<-c(2018-11-06,2018-11-06,2018-11-06,2018-11-09,2018-11-09,2018-11-09,2018-11-07,2018-11-07,2018-11-07,2018-11-05,2018-11-05,2018-11-05,2018-11-06,2018-11-06,2018-11-06...etc) 
tel<-c(0,0,1,1,0,1,1,1,0,1,1,1,0,0,1,...etc)       
porad<-c(1,2,3,1,2,3,1,2,3,1,2,3,1,2,3....etc)

我想创建带有结果的新列

E$de<-c(0,0,1,0,0,0,0,0,0,0,0,0,0,0,1,...etc)

所以我用了循环，这个过程大概跑了4个小时。

E$de[1]=ifelse(E$phone[i]==E$phone[i+1] & E$time[i]==E$time[i+1] & E$porad[1]==2 & E$tel[1]==1,1,0)
E$de[2]=ifelse(E$phone[i]==E$phone[i+1] & E$time[i]==E$time[i+1] & E$porad[2]==3 & E$tel[2]==1,1,0)
for (i in 3:length(E$phone))
{
  E$de[i]<-ifelse(E$phone[i]==E$phone[i-2] & E$time[i]==E$time[i-2] & E$porad[i]==3 & E$tel[i]==1 & E$tel[i-1]==0 & E$tel[i-2]==0,1,0)
}

请帮帮我：D

Answer 1

您可以通过向量化ifelse语句来避免循环或apply语句。

如果将i定义为3：length（E $ phone）的向量，则可以直接运行ifelse语句。

#test data
phone<-c(123,123,123,333,333,333,456,456,456,789,789,789,500,500,500)
time<-c("2018-11-06","2018-11-06","2018-11-06","2018-11-09","2018-11-09","2018-11-09",
        "2018-11-07","2018-11-07","2018-11-07","2018-11-05","2018-11-05", "2018-11-05", 
        "2018-11-06","2018-11-06","2018-11-06")
time<-as.Date(time)
tel<-c(0,0,1,1,0,1,1,1,0,1,1,1,0,0,1)
porad<-c(1,2,3,1,2,3,1,2,3,1,2,3,1,2,3)
E<-data.frame(phone, time, tel, porad)

E$de[1]=ifelse(E$phone[1]==E$phone[2] & E$time[1]==E$time[2] & E$porad[1]==2 & E$tel[1]==1,1,0)
E$de[2]=ifelse(E$phone[2]==E$phone[3] & E$time[2]==E$time[3] & E$porad[2]==3 & E$tel[2]==1,1,0)

#vectorized ifelse statement
i<-3:length(E$phone)
E$de[i]<-ifelse(E$phone[i]==E$phone[i-2] & E$time[i]==E$time[i-2] & E$porad[i]==3 & E$tel[i]==1 & E$tel[i-1]==0 & E$tel[i-2]==0,1,0)

这应该比for循环快约1000倍。