给出以下数据集（full.merge.sub）：
calltimes.full.x timezone.recode.x
1 2018-03-27 17:36:51 America/Detroit
2 2018-04-09 15:00:22 America/Detroit
3 2018-03-27 17:51:44 America/Detroit
4 2018-04-20 20:11:48 America/Detroit
5 2018-04-09 16:22:05 America/Detroit
6 2018-03-27 18:45:16 America/Detroit
7 2018-04-09 15:04:30 America/Detroit
8 2018-03-28 14:27:58 America/Chicago
9 2018-03-28 17:33:44 America/Chicago
10 2018-03-27 17:51:44 America/Detroit
以及以下用于转换时区的函数：
forceTZ <- function(x,tz)
{
return(as.POSIXct(format(x),tz=tz))
}
当我将函数置于循环中时，我得到的结果与单行调用函数时得到的结果不同：
for(i in 1:10){
if(is.na(full.merge.sub$timezone.recode.x[i])==FALSE){
full.merge.sub$calltime.converted.x[i]<-forceTZ(full.merge.sub$calltimes.full.x[i], full.merge.sub$timezone.recode.x[i])
}
}
summary(full.merge.sub[1:10,])
calltimes.full.x timezone.recode.x calltime.converted.x
Min. :2018-03-27 17:36:51 Length:10 Min. :1.522e+09
1st Qu.:2018-03-27 18:05:07 Class :character 1st Qu.:1.522e+09
Median :2018-03-28 16:00:51 Mode :character Median :1.522e+09
Mean :2018-04-03 05:04:36 Mean :1.523e+09
3rd Qu.:2018-04-09 15:03:28 3rd Qu.:1.523e+09
Max. :2018-04-20 20:11:48 Max. :1.524e+09
forceTZ(full.merge.sub$calltimes.full.x[1],full.merge.sub$timezone.recode.x[1])
[1] "2018-03-27 17:36:51 EDT"
> forceTZ(full.merge.sub$calltimes.full.x[1],full.merge.sub$timezone.recode.x[1])
[1] "2018-03-27 17:36:51 EDT"
> forceTZ(full.merge.sub$calltimes.full.x[2],full.merge.sub$timezone.recode.x[2])
[1] "2018-04-09 15:00:22 EDT"
> forceTZ(full.merge.sub$calltimes.full.x[3],full.merge.sub$timezone.recode.x[3])
[1] "2018-03-27 17:51:44 EDT"
> forceTZ(full.merge.sub$calltimes.full.x[4],full.merge.sub$timezone.recode.x[4])
[1] "2018-04-20 20:11:48 EDT"
> forceTZ(full.merge.sub$calltimes.full.x[5],full.merge.sub$timezone.recode.x[5])
[1] "2018-04-09 16:22:05 EDT"
> forceTZ(full.merge.sub$calltimes.full.x[6],full.merge.sub$timezone.recode.x[6])
[1] "2018-03-27 18:45:16 EDT"
> forceTZ(full.merge.sub$calltimes.full.x[7],full.merge.sub$timezone.recode.x[7])
[1] "2018-04-09 15:04:30 EDT"
> forceTZ(full.merge.sub$calltimes.full.x[8],full.merge.sub$timezone.recode.x[8])
[1] "2018-03-28 14:27:58 CDT"
> forceTZ(full.merge.sub$calltimes.full.x[9],full.merge.sub$timezone.recode.x[9])
[1] "2018-03-28 17:33:44 CDT"
> forceTZ(full.merge.sub$calltimes.full.x[10],full.merge.sub$timezone.recode.x[10])
[1] "2018-03-27 17:51:44 EDT"
我不知道为什么。
我可以尝试将新列转换为日期格式，如下所示：
as.POSIXct(full.merge.sub$calltime.converted.x,origin="1970-01-01")
但是结果仅仅是这样，而不是时区都一样，这对我没有用。
[1] "2018-03-27 17:36:51 EDT" "2018-04-09 15:00:22 EDT" "2018-03-27 17:51:44 EDT" "2018-04-20 20:11:48 EDT" "2018-04-09 16:22:05 EDT"
[6] "2018-03-27 18:45:16 EDT" "2018-04-09 15:04:30 EDT" "2018-03-28 15:27:58 EDT" "2018-03-28 18:33:44 EDT" "2018-03-27 17:51:44 EDT"
注意：已解决（有点）。如果在开始循环之前我将变量创建为POSIXct类变量，则它可以工作。但是，这似乎是一种奇怪的行为。