Question

我有两个这样的大数据集：

df1=data.frame(subject = c(rep(1, 12), rep(2, 10)), day =c(1,1,1,1,1,2,3,15,15,15,15,19,1,1,1,1,2,3,15,15,15,15),stime=c('4/16/2012 6:25','4/16/2012 7:01','4/16/2012 17:22','4/16/2012 17:45','4/16/2012 18:13','4/18/2012 6:50','4/19/2012 6:55','5/1/2012 6:28','5/1/2012 7:00','5/1/2012 16:28','5/1/2012 17:00','5/5/2012 17:00','4/23/2012 5:56','4/23/2012 6:30','4/23/2012 16:55','4/23/2012 17:20','4/25/2012 6:32','4/26/2012 6:28','5/8/2012 5:54','5/8/2012 6:30','5/8/2012 15:55','5/8/2012 16:30'))

df2=data.frame(subject = c(rep(1, 10), rep(2, 10)), day=c(1,1,2,2,3,3,9,9,15,15,1,1,2,2,3,3,9,9,15,15),dtime=c('4/16/2012 6:15','4/16/2012 15:16','4/18/2012 7:15','4/18/2012 21:45','4/19/2012 7:05','4/19/2012 23:17','4/28/2012 7:15','4/28/2012 21:12','5/1/2012 7:15','5/1/2012 15:15','4/23/2012 6:45','4/23/2012 16:45','4/25/2012 6:45','4/25/2012 21:30','4/26/2012 6:45','4/26/2012 22:00','5/2/2012 7:00','5/2/2012 22:00','5/8/2012 6:45','5/8/2012 15:45'))

...

在df2中，＆＃39; dtime＆＃39;每天包含两个时间点。我想在df1中每天使用每个sub的时间点（即＆＃39; stime＆＃39;）在df2中每天减去每个sub的第二个时间点，如果结果为正，则给出dtime中第二个时间点用于该观察，否则给出第一个时间点。例如，对于第1天的主题1（＆＃39; 2012年4月16日6:25＆＃39; - ＆＃39; 4/16/2012 15:16＆＃39;）＆lt; 0，我们给出第一个时间点＆＃39; 2012/4/16 6:15＆＃39;对这个障碍; （＆＃39; 2012年4月16日17:22＆＃39; - ＆＃39; 2012年4月16日15:16＆＃39;）＆gt; 0，所以我们给出第二个时间点＆lt; 4/16/2012 15:16＆＃39;对这个障碍。预期的输出应如下所示：

df3=data.frame(subject = c(rep(1, 12), rep(2, 10)), day =c(1,1,1,1,1,2,3,15,15,15,15,19,1,1,1,1,2,3,15,15,15,15),stime=c('4/16/2012 6:25','4/16/2012 7:01','4/16/2012 17:22','4/16/2012 17:45','4/16/2012 18:13','4/18/2012 6:50','4/19/2012 6:55','5/1/2012 6:28','5/1/2012 7:00','5/1/2012 16:28','5/1/2012 17:00','5/5/2012 17:00','4/23/2012 5:56','4/23/2012 6:30','4/23/2012 16:55','4/23/2012 17:20','4/25/2012 6:32','4/26/2012 6:28','5/8/2012 5:54','5/8/2012 6:30','5/8/2012 15:55','5/8/2012 16:30'), dtime=c('4/16/2012 6:15','4/16/2012 6:15','4/16/2012 15:16','4/16/2012 15:16','4/16/2012 15:16','4/18/2012 7:15','4/19/2012 7:05','5/1/2012 7:15','5/1/2012 7:15','5/1/2012 15:15','5/1/2012 15:15','.','4/23/2012 6:45','4/23/2012 6:45','4/23/2012 16:45','4/23/2012 16:45','4/25/2012 6:45','4/26/2012 6:45','5/8/2012 6:45','5/8/2012 6:45','5/8/2012 15:45','5/8/2012 15:45'))

...

我使用下面的代码来实现这一点，但是，由于缺少了“dtime＆time”。在第19天，R一直给我错误：

df1$dtime <- apply(df1, 1, function(x){  
                  choices <- df2[ df2$subject==as.numeric(x["subject"]) & 
                                       df2$day==as.numeric(x["day"]) , "dtime"]
         if( as.POSIXct(x["stime"], format="%m/%d/%Y %H:%M") < 
                 as.POSIXct(choices[2],format="%m/%d/%Y %H:%M") ) {
            choices[1] 
            }else{ choices[2] } 
                                  } )

Error in if (as.POSIXct(x["stime"], format = "%m/%d/%Y %H:%M") < as.POSIXct(choices[2],  : missing value where TRUE/FALSE needed

由于我的数据集很大（大约15,000行和30列），因此有一些缺失的＆d; dtime＆＃39;在df2。有谁知道如何解决这个问题？

Answer 1

我认为这可能适合你：

df1$dtime <- apply(df1, 1, function(x) {

  choices <- as.character(df2[ df2$subject==as.numeric(x["subject"]) & 
                  df2$day==as.numeric(x["day"]), "dtime"])

  t1 <- as.POSIXct(as.character(x["stime"]), format="%m/%d/%Y %H:%M")
  t2 <- as.POSIXct(choices[2], format="%m/%d/%Y %H:%M")

  return(ifelse(( t1 < t2 ), choices[1], choices[2]))

})

使用来自两个数据集的信息创建新列导致的缺失值问题

1 个答案: