小编cha*_*sno的帖子

我有如下数据集:

> head(worldcup)
               Team   Position Time Shots Passes Tackles Saves
Abdoun      Algeria Midfielder   16     0      6       0     0
Abe           Japan Midfielder  351     0    101      14     0
Abidal       France   Defender  180     0     91       6     0
Abou Diaby   France Midfielder  270     1    111       5     0
Aboubakar  Cameroon    Forward   46     2     16       0     0
Abreu       Uruguay    Forward   72     0     15       0     0

然后是某些变量的代码计数平均值:

wc_3 <- worldcup %>% 
  select(Time, Passes, Tackles, Saves) %>%
  summarize(Time = mean(Time),
            Passes = mean(Passes),
            Tackles = mean(Tackles),
            Saves = …

我试图通过修改我的脚本在 R 中进行并行编程。在我的脚本上，我做了两个并行编程。第一个已经完成，但第二个是错误的，而脚本结构是相同的。下面是我的代码：

library(rvest)
library(RMySQL)
library(curl)
library(gdata)
library(doMC)
library(foreach)
library(doParallel)
library(raster)


trim <- function (x) gsub("^\\s+|\\s+$", "", x)

setwd('/home/chandra/R/IlmuOne/MisterAladin')

no_cores <- detectCores() 
cl<-makeCluster(no_cores)
registerDoParallel(cl)

MasterData = read.xls("Master Hotels - FINAL.xlsx", sheet = 1, header = TRUE)
MasterData$url_agoda = as.character(MasterData$url_agoda)

today = as.Date(format(Sys.time(), "%Y-%m-%d"))+2

ntasks <- nrow(MasterData)

#This section perfomed well
foreach(i=1:ntasks) %dopar% {    
  url = MasterData$url_agoda[i]        
  if (trim(url)!='-' & trim(url)!='')
  {
    from = gregexpr(pattern ='=',url)[[1]][1]
    piece1 = substr(url,1,from)
    from = gregexpr(pattern ='&los=',url)[[1]][1]
    piece2 = substr(url,from,nchar(url))
    MasterData$url_agoda[i] = paste0(piece1,today,piece2)  
  }   
} …