Re: [問題] Json to R and Data talbe/matrix arrange

看板R_Language作者peterwu76 (金岡)時間8年前 (2017/06/07 09:32)推噓0(0推 0噓 11→)

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感謝 celestialgod 前輩的幫忙附上最後的code for download historical data，這樣也可以讓前輩了解我想做什麼。好讀版 https://hackmd.io/KwU2CMDMENQWmAZgEwGM4BZrmXcB2AThDmn2GQBNxKAGDVYYIA==?both 備註說明: 原本也想考慮抓Realtime數據，結果發現抓出來的資料時間跟歷史資料最新的data時間是一樣的，抓取資料的時間點跟最新能抓到的資料的時間點相隔8小時左右。舉例來說，我09:00使用此code抓資料，抓出的資料最後(最新的)一筆資料的時間大概是01:00。所以最後放棄所謂Realtime抓資料的想法，不如抓歷史historical資料。 MY Final codes for historical data # Get data from Json link library(jsonlite) url <- "https://data.lass-net.org/data/history.php?device_id=74DA38C7D1D2" x <- fromJSON(url) # Arrange data into table matrix library(data.table) library(lubridate) outDT <- rbindlist(x$feeds$AirBox) # Claim the timestamp into correct time format by lubridate package outDT[ , `:=`(source = x$source, version = ymd_hms(x$version), device_id = x$device_id, timestamp = ymd_hms(timestamp))] sortD <- outDT # Capture data by column names headers<-c("timestamp","s_d0","s_t0","s_h0","date","time","device_id","gps_lon","gps_lat","version") sortD <- subset(outDT,select=headers) # rename column names colnames(sortD)[which(names(sortD) == "s_d0")] <- "PM2.5" colnames(sortD)[which(names(sortD) == "s_t0")] <- "Temperature" colnames(sortD)[which(names(sortD) == "s_h0")] <- "Humidity" # Sort data sortD$timestamp <- as.POSIXct(sortD$timestamp, tz='UTC') class(sortD$timestamp) Final_data<-sortD[order(sortD$timestamp)] View(Final_data) # Output data date <- sprintf("AirBox_74DA38C7D1D2_%s.csv", format(Sys.time(),"%Y%m%d%H%M")) outfile = paste("D:\\AirBoxTest\\", date, sep = "") write.csv(Final_data, file = outfile) ################################# # Hourly average and output ################################# Final_data_hourly<- aggregate(list(PM2.5 = Final_data$PM2.5, Humidity = Final_data$Humidity, Temperature = Final_data$Temperature), list(hourofday = cut(Final_data$timestamp, "1 hour")), mean) # Output data date <- sprintf("AirBox_74DA38C7D1D2_Hourly_%s.csv", format(Sys.time(),"%Y%m%d%H%M")) outfile = paste("D:\\AirBoxTest\\", date, sep = "") write.csv(Final_data_hourly, file = outfile) -- ※ 發信站: 批踢踢實業坊(ptt.cc), 來自: 140.112.1.187 ※ 文章網址: https://www.ptt.cc/bbs/R_Language/M.1496799136.A.80A.html