我有两个数据帧:
轨迹:
Date Time Temperature Voltage Longitude Latitude Deployment DateTime
2014-08-08 14:18:25 20.9 1.872 -126.6886 34.95633 A 2014-08-08 14:20:00
2014-08-08 14:38:25 19.8 1.862 -126.6899 34.95675 A 2014-08-08 14:40:00
2014-08-08 14:58:26 19.3 1.856 -126.6911 34.95732 A 2014-08-08 15:00:00
2014-08-08 15:18:26 18.8 1.872 -126.6921 34.95803 A 2014-08-08 15:20:00
2014-08-08 15:38:25 18.6 1.872 -126.6929 34.95872 A 2014-08-08 15:40:00
2014-08-08 15:58:26 18.4 1.859 -126.6937 34.95921 A 2014-08-08 16:00:00
2014-08-08 16:18:25 18.4 1.875 -126.6944 34.95983 A 2014-08-08 16:20:00
2014-08-08 16:38:25 18.4 1.875 -126.6949 34.96021 A 2014-08-08 16:40:00
2014-08-08 16:58:26 18.4 1.872 -126.6956 34.96033 A 2014-08-08 17:00:00
2014-08-08 17:18:26 18.4 1.872 -126.6962 34.96025 A 2014-08-08 17:20:00
和数据:
FileName Deployment Start_UTC Stop_UTC Duration sum PrAb dolPrAb
DASBR1_20140808$140000.wav A 2014-08-08 14:00:00 2014-08-08 14:02:00 119.6000 0 0 0
DASBR1_20140808$142000.wav A 2014-08-08 14:20:00 2014-08-08 14:22:00 119.6000 0 0 0
DASBR1_20140808$144000.wav A 2014-08-08 14:40:00 2014-08-08 14:42:00 119.8000 0 0 0
DASBR1_20140808$150000.wav A 2014-08-08 15:00:00 2014-08-08 15:02:00 119.6000 0 0 0
DASBR1_20140808$152000.wav A 2014-08-08 15:20:00 2014-08-08 15:22:00 119.6000 0 0 0
DASBR1_20140808$154000.wav A 2014-08-08 15:40:00 2014-08-08 15:42:00 119.6000 0 0 0
DASBR1_20140808$160000.wav A 2014-08-08 16:00:00 2014-08-08 16:02:00 119.6000 1 1 1
DASBR1_20140808$162000.wav A 2014-08-08 16:20:00 2014-08-08 16:22:00 119.8000 0 0 0
DASBR1_20140808$164000.wav A 2014-08-08 16:40:00 2014-08-08 16:42:00 119.8000 0 0 0
DASBR1_20140808$170000.wav A 2014-08-08 17:00:00 2014-08-08 17:02:00 119.6000 0 0 0
实际上每个都有几千行长。我想合并他们基于"DateTime"戳在locA和"Start_UTC"在datA。这两个列在UTC中被格式化为相同的格式。
locA$DateTime=as.POSIXct(paste(locA$Date, time), format="%Y-%m-%d %H:%M:%S", tz="UTC")
datA$Start_UTC = as.POSIXct(files$Start_UTC, format="%Y-%m-%d %H:%M:%S", tz="UTC")
在locA中，"time"变量来自于一个序列，我将locA$ time中的字符串四舍五入到最接近的20min。time是一个字符串，其中包含调整后的时间。
str(time)
chr [1:8845] "14:00:00" "14:20:00" "14:40:00" "15:00:00" "15:20:00" "15:40:00" "16:00:00" "16:20:00" "16:40:00" "17:00:00" ...
当我使用locA$DateTime和data $Start_UTC合并两个数据帧时，它永远不会正常工作。每次都会得到这样的结果。
resA = merge(datA,locA, by.x=c("Start_UTC"), by.y=c("DateTime"))
resA:
Start_UTC FileName Deployment.x Stop_UTC Duration sum PrAb dolPrAb Date Time Temperature Voltage Longitude Latitude Deployment.y
2014-08-08 14:00:00 DASBR1_20140808$140000.wav A 2014-08-08 14:02:00 119.6000 0 0 0 2014-08-08 20:58:26 19.1 1.872 -126.7018 34.94994 A
2014-08-08 14:20:00 DASBR1_20140808$142000.wav A 2014-08-08 14:22:00 119.6000 0 0 0 2014-08-08 21:18:26 19.1 1.872 -126.7027 34.94801 A
2014-08-08 14:40:00 DASBR1_20140808$144000.wav A 2014-08-08 14:42:00 119.8000 0 0 0 2014-08-08 21:38:26 19.1 1.872 -126.7038 34.94608 A
2014-08-08 15:00:00 DASBR1_20140808$150000.wav A 2014-08-08 15:02:00 119.6000 0 0 0 2014-08-08 21:58:27 18.9 1.865 -126.7050 34.94394 A
2014-08-08 15:20:00 DASBR1_20140808$152000.wav A 2014-08-08 15:22:00 119.6000 0 0 0 2014-08-08 22:18:27 18.9 1.856 -126.7062 34.94188 A
2014-08-08 15:40:00 DASBR1_20140808$154000.wav A 2014-08-08 15:42:00 119.6000 0 0 0 2014-08-08 22:38:26 18.8 1.862 -126.7077 34.93994 A
2014-08-08 16:00:00 DASBR1_20140808$160000.wav A 2014-08-08 16:02:00 119.6000 1 1 1 2014-08-08 22:58:26 18.8 1.859 -126.7090 34.93796 A
2014-08-08 16:20:00 DASBR1_20140808$162000.wav A 2014-08-08 16:22:00 119.8000 0 0 0 2014-08-08 23:18:26 18.8 1.865 -126.7105 34.93622 A
2014-08-08 16:40:00 DASBR1_20140808$164000.wav A 2014-08-08 16:42:00 119.8000 0 0 0 2014-08-08 23:38:27 18.6 1.856 -126.7120 34.93480 A
2014-08-08 17:00:00 DASBR1_20140808$170000.wav A 2014-08-08 17:02:00 119.6000 0 0 0 2014-08-09 23:58:28 18.8 1.849 -126.8051 34.88381 A
我已经尝试了很多不同的方法。我尝试保持locA$DateTime原样，其中时间等于datA$ time中的时间戳，然后尝试使用此函数将其与正确的datA$Start_UTC匹配。将最小的locala $timestamp与datA$timestamp
匹配findrow=function(dt,df) {min(which(df>dt))}
rowA=sapply(locA$DateTime, findrow, df=datA$Start_UTC)
resA=cbind(locA,datA[rowA,])
这给了我相同的结果。我不知道发生了什么。我确信这是生成日期时间戳的内在原因，但我不知道如何解决这个问题。如果我将它们格式化为相同的格式，并告诉R它们是UTC，它们不应该以相同的方式处理吗?
帮助，请，所有的帮助，评论，或幽默的"坚持住"语句将非常感激。不能正确配对我的晚/长与我的数据时间戳是真正引起头痛。
欢呼。
我想知道是否在chr对象上做合并而不是POSIXct对象会更好?
locA$DateTime_str = format(locA$DateTime)
datA$Start_UTC_str = format(datA$Start_UTC)
resA = merge(datA,locA, by.x=c("Start_UTC_str"), by.y=c("DateTime_str"))