用于R中的循环

我试图在Shiny中创建一个应用程序，它以某种方式接收输入并返回输入。该守则应按如下方式运作：

输入是一个表，称为trips，通过以下方式进行：

>head(trips)
  time.start   time.end long.start long.end lat.start  lat.end
1 1476450598 1476450713    9.03913  9.03924  45.61335 45.61362
2 1476450713 1476450727    9.03924  9.03995  45.61362 45.61365
3 1476450727 1476450751    9.03995  9.04005  45.61365 45.61340
4 1476450751 1476450777    9.04005  9.04017  45.61340 45.61406
5 1476450777 1476450873    9.04017  9.03949  45.61406 45.61419
6 1476450873 1476450920    9.03949  9.03496  45.61419 45.61319

操作如下（在标准R环境中）

正如你所看到的，这并没有什么特别的，尽管在R中，Shiny并没有像预期的那样工作。下面是代码：

第一部分是获取初始trips表，所有工作都很顺利

trips<-reactive({
    data.frame(
    time.start=as.numeric((substr(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$recorded_at,1,10)))[1:(length(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$recorded_at)-1)],
    time.end=as.numeric((substr(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$recorded_at,1,10)))[2:(length(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$recorded_at))],
    long.start=matrix((as.vector(unlist(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$loc, recursive = TRUE))),ncol=2,byrow=T)[1:dim(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2])))[1]-1,1],
    long.end=matrix((as.vector(unlist(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$loc, recursive = TRUE))),ncol=2,byrow=T)[2:dim(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2])))[1],1],
    lat.start=matrix((as.vector(unlist(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$loc, recursive = TRUE))),ncol=2,byrow=T)[1:dim(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2])))[1]-1,2],
    lat.end=matrix((as.vector(unlist(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$loc, recursive = TRUE))),ncol=2,byrow=T)[2:dim(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2])))[1],2]
  )[-(cumsum(sapply(lapply(res.clean()[,2],fromJSON), dim)[1,])),]
  })

有什么我遗漏的吗

---

感谢您的帮助

您正在反复呼叫trips1。每次使用

trips1（）

时，它都在运行反应函数。反动剂不是那样的。当您调用

renderTable（trips1（））

时，它或多或少地调用了

renderTable（trips1（trips1（…））

谢谢您的帮助，我如何更改代码以使其正常工作？请尝试类似以下操作：

triploop
> head(trips)
  time.start   time.end long.start long.end lat.start  lat.end  distance time.diff      speed color
1 1476450598 1476450713    9.03913  9.03924  45.61335 45.61362  31.25292       115  0.9783524 green
2 1476450713 1476450727    9.03924  9.03995  45.61362 45.61365  55.38651        14 14.2422459 green
3 1476450727 1476450751    9.03995  9.04005  45.61365 45.61340  28.89870        24  4.3348057 green
4 1476450751 1476450777    9.04005  9.04017  45.61340 45.61406  74.06267        26 10.2548313 green
5 1476450777 1476450873    9.04017  9.03949  45.61406 45.61419  54.89125        96  2.0584219 green
6 1476450873 1476450920    9.03949  9.03496  45.61419 45.61319 369.88687        47 28.3317600 green

trips<-reactive({
    data.frame(
    time.start=as.numeric((substr(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$recorded_at,1,10)))[1:(length(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$recorded_at)-1)],
    time.end=as.numeric((substr(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$recorded_at,1,10)))[2:(length(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$recorded_at))],
    long.start=matrix((as.vector(unlist(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$loc, recursive = TRUE))),ncol=2,byrow=T)[1:dim(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2])))[1]-1,1],
    long.end=matrix((as.vector(unlist(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$loc, recursive = TRUE))),ncol=2,byrow=T)[2:dim(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2])))[1],1],
    lat.start=matrix((as.vector(unlist(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$loc, recursive = TRUE))),ncol=2,byrow=T)[1:dim(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2])))[1]-1,2],
    lat.end=matrix((as.vector(unlist(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2]))$loc, recursive = TRUE))),ncol=2,byrow=T)[2:dim(do.call(rbind,lapply(lapply(res.clean()[,2],fromJSON),function(x) x[,1:2])))[1],2]
  )[-(cumsum(sapply(lapply(res.clean()[,2],fromJSON), dim)[1,])),]
  })

trips1<-reactive({

  for (i in 1:dim(trips())[1])

    {
    trips1()$distance[i]<-as.numeric(distm(c(trips()$long.start[i],trips()$lat.start[i]), c(trips()$long.end[i],trips()$lat.end[i]), fun = distHaversine))
    trips1()$time.diff[i]<-as.numeric(difftime(anytime(trips()$time.end[i]),anytime(trips()$time.start[i])),units="secs")
    trips1()$speed[i]<-if (trips()$distance[i] ==0) {0} else{
      (trips1()$distance[i]/as.numeric(difftime(anytime(trips()$time.end[i]),
                                             anytime(trips()$time.start[i])),units="secs"))*3.6}
    trips1()$color[i]<-if(trips()$speed[i] < 50){"green"} else if (trips()$speed[i] < 70){"yellow"}else if (trips()$speed[i] > 70){"red"}
  }

})

output$table <- renderTable(trips1())

invalid (NULL) left side of assignment