R清理csv文件答案

【问题标题】：R cleaning csv fileR清理csv文件
【发布时间】：2016-05-17 15:11:56
【问题描述】：

我正在研究天气数据。我正在尝试清理 csv 文件，但不断出现奇怪的错误。在 csv 文件中，9999 和 -9999 是空值。我想删除一半以上值为 9999 或 -9999 的所有列。我读了 csv 文件。然后将一个空矩阵初始化为与读取 csv 文件时创建的数据框相同的维度。我遍历数据框“文件”中的列，检查是否有任何值是 na 或空字符串。我创建了一个向量“元”并从 plyr 库中调用 count 来聚合数据框中的所有列。然后我遍历行并检查是否有任何 na 值在行中，然后我检查 9999 或 -9999 是否在向量元的行中。然后，我查看的频率是否大于列中行数的一半。如果是，则将值添加到干净的矩阵中。我不断收到奇怪的错误，并且干净矩阵中的值不是我预期的。我将附上两者的屏幕截图。我还将附上 csv 文件和 R 代码。

谢谢

errors values in the clean matrix 1

file <- read.csv(header = TRUE, file = "C:\\Users\\michael.guarino1\\Desktop\\weather\\nov_6_2012\\735144.csv")
clean <- matrix(0, nrow(file), ncol(file))#initialize matrix of same dimensions as file
library(plyr)
count <- 1 #initialize count to 1
for (i in 1:ncol(file)) {
  if (!any(is.na(file[,i]))|!any(file[,i]==" ")) { 
    meta <- count(file, i)
    for(row in 1:nrow(meta)){
     if(!is.na(meta[row,1])){
       if (meta[row,1]== -9999 | meta[row,1]== 9999) {
         print("condition 1 found")

         if (meta$freq < (nrow(file) / 2)) {
           print("condition 2 found")
           clean[, count] <- file[, i]

           count <- count + 1
         }
       }
     }

      #else{
       # clean[, count] <- file[, i]
        #count <- count + 1
     # }  
    }

  }
  else{ 
    next
  }
}
print("meta")
print(meta)
print("clean")
print(clean)


    STATION,STATION_NAME,ELEVATION,LATITUDE,LONGITUDE,DATE,MDPR,Measurement Flag,Quality Flag,Source Flag,Time of Observation,MDSF,Measurement Flag,Quality Flag,Source Flag,Time of Observation,DAPR,Measurement Flag,Quality Flag,Source Flag,Time of Observation,DASF,Measurement Flag,Quality Flag,Source Flag,Time of Observation,PRCP,Measurement Flag,Quality Flag,Source Flag,Time of Observation,SNWD,Measurement Flag,Quality Flag,Source Flag,Time of Observation,SNOW,Measurement Flag,Quality Flag,Source Flag,Time of Observation,TMAX,Measurement Flag,Quality Flag,Source Flag,Time of Observation,TMIN,Measurement Flag,Quality Flag,Source Flag,Time of Observation,TOBS,Measurement Flag,Quality Flag,Source Flag,Time of Observation,PGTM,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT09,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT07,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT01,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT06,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT05,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT02,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT11,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT04,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT16,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT08,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT18,Measurement Flag,Quality Flag,Source Flag,Time of Observation,WT03,Measurement Flag,Quality Flag,Source Flag,Time of Observation
GHCND:USR0000IPOB,POTTER BUTTE IDAHO ID US,1502.7,43.2261,-113.5744,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,40,H, ,U,9999,30,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USW00004842,WOOSTER WAYNE CO AIRPORT OH US,346.6,40.87306,-81.88667,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999,71, , ,W,9999,40, , ,W,9999,-9999, , , ,9999,1605, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999,1, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,1, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USW00003954,OKLAHOMA CITY WILEY POST AIRPORT OK US,395.3,35.53417,-97.64694,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999,77, , ,W,9999,57, , ,W,9999,-9999, , , ,9999,1531, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00080737,BIG CYPRESS FL US,4.6,26.32833,-80.99583,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,0,0800,0.0,P, ,0,9999,0.0,P, ,0,9999,82, , ,0,0800,65, , ,0,0800,65, , ,0,0800,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000OBRI,BRER RABBIT OREGON OR US,1798.3,44.3231,-119.7669,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,31,H, ,U,9999,22,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00202381,EAST JORDAN MI US,178.3,45.1519,-85.1322,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,0,1500,0.0, , ,0,1500,0.0, , ,0,9999,74, , ,0,1500,43, , ,0,1500,74, , ,0,1500,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,1, , ,0,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000CKON,KONOCTI CALIFORNIA CA US,659.3,38.9119,-122.7064,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,49,H, ,U,9999,40,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000MBLA,BLACKWATER MARYLAND MD US,426.7,38.4167,-76,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,61,H, ,U,9999,54,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000WEST,ESTERBROOK WYOMING WY US,1990.3,42.4153,-105.3611,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,56,H, ,U,9999,32,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:US1GAGW0006,BUFORD 4.6 ESE GA US,352.7,34.0799,-83.9313,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,N,9999,-9999, , , ,9999,0.0, , ,N,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00111290,CARLYLE RESERVOIR IL US,152.7,38.63083,-89.36583,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,0,0800,0.0,P, ,0,9999,0.0,P, ,0,9999,76, , ,0,0800,46, , ,0,0800,49, , ,0,0800,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00116661,PAW PAW 2 S IL US,289.6,41.71222,-88.99889,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,0,0700,0.0, , ,0,9999,0.0, , ,0,9999,72, , ,0,0700,47, , ,0,0700,48, , ,0,0700,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000MSUN,SUNKHAZE MEADOWS MAINE ME US,34.7,44.9031,-68.64,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,63,H, ,U,9999,35,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000MAVA,AVA MISSOURI MO US,399.6,36.9431,-92.65,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,73,H, ,U,9999,44,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000JEBF,EB FORSYTHE NEW JERSEY NJ US,396.2,39.5,-74.5,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,60,H, ,U,9999,51,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000ADVK,DEVILS KNOB ARKANSAS AR US,640.1,35.6111,-93.3333,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,65,H, ,U,9999,54,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00228556,SUMRALL MS US,88.4,31.42222,-89.53861,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00,P, ,0,0700,0.0,P, ,0,9999,0.0,P, ,0,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000TDAY,DAYTON TEXAS TX US,30.5,30.105,-94.9314,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,79,H, ,U,9999,48,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00340292,ARDMORE OK US,268.2,34.17139,-97.12944,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,0,0800,0.0,P, ,0,9999,0.0,P, ,0,9999,78, , ,0,0800,60, , ,0,0800,67, , ,0,0800,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:US1PALN0003,ADAMSTOWN 2.5 SSE PA US,198.1,40.2055,-76.0509,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00,T, ,N,9999,-9999, , , ,9999,0.0, , ,N,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00408522,SPARTA WASTEWATER PLANT TN US,310.9,35.9566,-85.4813,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,0,0700,0.0,P, ,0,9999,0.0,P, ,0,9999,75, , ,0,0700,36, , ,0,0700,39, , ,0,0700,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000WGOL,GOLD MOUNTAIN WASHINGTON WA US,1428.3,48.1806,-118.4636,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,33,H, ,U,9999,27,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:US1FLAL0007,GAINESVILLE 8.1 SW FL US,36.9,29.5908,-82.4314,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,N,9999,-9999, , , ,9999,0.0, , ,N,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00148341,VALLEY FALLS KS US,299.3,39.3033,-95.4861,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,0,0700,0.0,P, ,0,0700,0.0,P, ,0,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000IHAR,HARDIN RIDGE INDIANA IN US,228.6,39,-86.4228,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,76,H, ,U,9999,43,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USW00014742,BURLINGTON INTERNATIONAL AIRPORT VT US,100.6,44.46806,-73.15028,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,0,2400,0.0, , ,0,9999,0.0, , ,0,9999,61, , ,0,2400,46, , ,0,2400,-9999, , , ,9999,941, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999,1, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,1, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000SWIT,WITHERBEE SOUTH CAROLINA SC US,18,33.1597,-79.8306,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,62,H, ,U,9999,59,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00367782,SALINA 3 W PA US,338,40.5101,-79.5459,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,0,0700,0.0,P, ,0,0700,0.0,P, ,0,9999,69, , ,0,0700,43, , ,0,0700,44, , ,0,0700,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000CANZ,ANZA CALIFORNIA CA US,1194.8,33.555,-116.673,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,53,H, ,U,9999,42,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:US1KSEL0043,HAYS 5.4 SSW KS US,630.6,38.8129,-99.3735,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,N,9999,-9999, , , ,9999,0.0, , ,N,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000ATAL,TALLADEGA ALABAMA AL US,182.9,33.4411,-86.0811,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,76,H, ,U,9999,44,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USW00094985,MARSHFIELD MUNICIPAL AIRPORT WI US,382.5,44.63806,-90.1875,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999,73, , ,W,9999,53, , ,W,9999,-9999, , , ,9999,1436, , ,W,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000ISLA,SLATE CREEK IDAHO ID US,477.9,45.6333,-116.2833,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,51,H, ,U,9999,41,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000MDRY,DRY BLOOD CREEK MONTANA MT US,914.4,47.2442,-108.3575,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,53,H, ,U,9999,38,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00134142,IOWA FALLS IA US,321.6,42.5188,-93.2536,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00,P, ,0,0700,0.0,P, ,0,9999,0.0,P, ,0,9999,75, , ,0,0700,52, , ,0,0700,55, , ,0,0700,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00161565,CARVILLE 2 SW LA US,7.6,30.19806,-91.12556,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,0,2400,0.0,P, ,0,9999,0.0,P, ,0,9999,77, , ,0,2400,51, , ,0,2400,58, , ,0,2400,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USR0000NSTO,STONYKILL NEW YORK NY US,61,41.5,-73.9,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,63,H, ,U,9999,40,H, ,U,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:US1ALMD0040,HAMPTON COVE 0.5 NNW AL US,187.1,34.667,-86.485,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.00, , ,N,9999,-9999, , , ,9999,0.0, , ,N,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999
GHCND:USC00421446,CITY CRK WATER PLANT UT US,1624.6,40.8397,-111.8313,20081104,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,0.62, , ,0,1600,1.0, , ,0,1600,1.3, , ,0,9999,52, , ,0,1600,32, , ,0,1600,40, , ,0,1600,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999,-9999, , , ,9999

【问题讨论】：

警告：切勿在代码中对数据文件使用绝对路径，这会使代码完全无法重现（在其他机器上，甚至在您更改文件）。相反，对您的项目的数据进行逻辑分组并使用相对路径。
我不明白你为什么在这里如此疯狂。 apply(file,2,function(x){sum(abs(x)==9999)}) 将计算每列中 9999 和 -9999 的数量。然后仅对该值超过行数一半的列进行子集化。它是一个两班...
您的代码无法运行。你做count <- 1 然后尝试使用count 就像一个函数：meta <- count(file, i)。那应该怎么做？
这个问题需要一些可重复的例子。

标签： r file csv

【解决方案1】：

假设您的数据如下所示：

df <- data.frame(v1 = c(1,1,2,1,2,1),
                 v2 = c(9999, 1, 2, 1, 2, -9999), 
                 v3 = c(9999, 1, -9999, 9999, 2, -9999))

然后，您可以使用colSums 删除值超过一半的列，即 9999 或 -9999：

df[ , colSums(abs(df) == 9999)/nrow(df) < 0.5]

或colMeans:

df[ , colMeans(abs(df) == 9999) < 0.5]

这都会导致删除v3-column：

【讨论】：

【解决方案2】：

# Some made up data...

A<-as.integer(runif(10,1,40))
B<-as.integer(runif(10,1,40))
C<-as.integer(runif(10,1,40))
D<-as.integer(runif(10,1,40))
E<-as.integer(runif(10,1,40))
rlist<-data.frame(A,B,C,D,E)
rlist$A[rlist$A %% 2 == 0]=9999
rlist$C[rlist$C %% 2 == 0]= -9999
rlist$E[rlist$E %% 2 == 0]=9999

print(rlist)

#Now make "-9999" and "9999" into NA's

rlist[rlist[,]==9999|rlist[,]==-9999]<-NA

print(rlist)

#Now we need a function to figure out if >50% of a list is NA
is.most.NA<-function(x){
    mean(is.na(x))<=.5
    }

#Now apply the function to the columns  

rlist[,apply(rlist,2,is.most.NA)]

【讨论】：

【解决方案3】：

这样的事情应该会有所帮助。

count9999 <- function(x) {
    r1 <- sum(x == 9999) / length(x)
    r2 <- sum(x == -9999) / length(x)
    if (r1 > 0.5 | r2 > 0.5) {
        return(FALSE)
    } else {
        return(TRUE)
    }
}

file <- file[, apply(file, 2, count9999 )]

【讨论】：

这将删除您不需要的所有列