我有一份包含超过3百万条记录的数据,其中start.time和end.time是两个变量。前10个记录如下:
start.date start.time end.date end.time
1 2012-07-13 15:01:32 2012-07-13 15:02:42
2 2012-07-05 18:26:31 2012-07-05 18:27:19
3 2012-07-14 20:23:21 2012-07-14 20:24:11
4 2012-07-29 16:09:54 2012-07-29 16:10:48
5 2012-07-21 14:58:32 2012-07-21 15:00:17
6 2012-07-04 15:36:31 2012-07-04 15:37:11
7 2012-07-22 18:28:31 2012-07-22 18:28:50
8 2012-07-09 21:08:42 2012-07-09 21:09:02
9 2012-07-05 09:44:52 2012-07-05 09:45:05
10 2012-07-02 18:50:47 2012-07-02 18:51:38
我需要计算开始时间和结束时间之间的差值。
我使用了以下代码:
mbehave11$diff.time <- difftime(mbehave11$end.time, mbehave11$start.time, units="secs")
但是我遇到了这个错误:
Error in as.POSIXlt.character(x, tz, ...) :
character string is not in a standard unambiguous format
In addition: Warning messages:
1: In is.na.POSIXlt(strptime(xx, f <- "%Y-%m-%d %H:%M:%OS", tz = tz)) :
Reached total allocation of 1535Mb: see help(memory.size)