Question

我有一个非常大的数据集，我想将其绘制成传单，但是我使用的“ for循环”需要很长时间。有人告诉我使用mapply函数会更快，但是我不知道如何将for循环转换为mapply。

我的最终目的是使我的代码运行得更快。

看一下我的数据集和地图结果的例子：

#import libraries:

library(data.table)
library(leaflet) 

#dataset:


lat<-c(40.41766, 40.43305 ,40.43687, 40.39563, 40.39088, 40.39215, 40.39458, 40.40451, 40.40627, 40.40864)

lng<-c(-3.701328, -3.709352, -3.708531, -3.736556, -3.734796, -3.741867, -3.741222, -3.705399, -3.710980, -3.710310)

colors<-c("#3D00FFFF","#52FF00FF","#3D00FFFF","#0052FFFF","#52FF00FF","#52FF00FF","#52FF00FF","#0052FFFF","#3D00FFFF","#0052FFFF")

name<-c("Rafa","Luis","Rafa","Belen","Luis","Luis","Luis","Belen","Rafa","Belen")

hour_range<-c("Sleeping_Hours","Morning_rush_hours","Morning_Working_Hours","Sleeping_Hours","Morning_rush_hours","Morning_Working_Hours","Sleeping_Hours","Morning_rush_hours","Morning_Working_Hours","Morning_Working_Hours")

data<- data.table(name,lat,lng,hour_range,colors)

#As you can see the data.table has 5 variables (name, lat, lng, hour_range,colors)

#My objective is to plot in leaflet a line of every person (name)in a 
#different color and also with 1 layer for each hour_range).

#I was able to do so with a for loop:

map<-  leaflet(data)
map<- addTiles(map)

for( name in unique(data$name)){ 
  map<- addPolylines(map, lng=~lng,lat=~lat,data=data[data$name==name & data$hour_range=="Sleeping_Hours",], group= "Sleeping_Hours",color=~colors)
  map<- addPolylines(map, lng=~lng,lat=~lat,data=data[data$name==name & data$hour_range=="Morning_rush_hours",], group= "Morning_rush_hours",color=~colors)
  map<- addPolylines(map, lng=~lng,lat=~lat,data=data[data$name==name & data$hour_range=="Morning_Working_Hours",], group= "Morning_Working_Hours",color=~colors)


}
map<-addLayersControl(map=map,
                             overlayGroups=c("Sleeping_Hours","Morning_rush_hours","Morning_Working_Hours"),
                             options=layersControlOptions(collapsed=FALSE)

map

此地图可以正常工作，因为它是一个较小的数据集，但如果数据集较长，则不起作用，如何使它运行得更快？我如何在这里应用mapply函数而不是循环？

谢谢！

对于浪费大量内存的循环，请更改为mapply吗？

0 个答案: