Hi,You haven't provided any example dataset.
?set.seed(42)
?dat1 <- data.frame(dates=seq(as.POSIXct("2009-01-01
00:00:00",format="%Y-%m-%d %H:%M:%S"),by= '12 hour',
length=12),Field1=rnorm(12),Field2=LETTERS[1:12])
set.seed(395)
?dat2 <- data.frame(dates=seq(as.POSIXct("2009-01-01
00:00:00",format="%Y-%m-%d %H:%M:%S"),by= '6 hour',
length=12),Field1=rnorm(12),Field2=sample(LETTERS,12,replace=FALSE))
merge(dat1,dat2,by="dates")
#??????????????? dates?? Field1.x Field2.x?? Field1.y Field2.y
#1 2009-01-01 00:00:00? 1.3709584??????? A -1.2152900??????? V
#2 2009-01-01 12:00:00 -0.5646982??????? B -1.2771657??????? P
#3 2009-01-02 00:00:00? 0.3631284??????? C? 0.4829300??????? W
#4 2009-01-02 12:00:00? 0.6328626??????? D? 0.5468625??????? Y
#5 2009-01-03 00:00:00? 0.4042683??????? E -1.7113256??????? I
#6 2009-01-03 12:00:00 -0.1061245??????? F? 0.4851851??????? B
merge(dat1,dat2,by="dates",all=TRUE)[1:5,]
??????????????? dates?? Field1.x Field2.x?? Field1.y Field2.y
1 2009-01-01 00:00:00? 1.3709584??????? A -1.2152900??????? V
2 2009-01-01 06:00:00???????? NA???? <NA> -0.4633211??????? G
3 2009-01-01 12:00:00 -0.5646982??????? B -1.2771657??????? P
4 2009-01-01 18:00:00???????? NA???? <NA>? 0.6011199??????? N
5 2009-01-02 00:00:00? 0.3631284??????? C? 0.4829300??????? W
A.K.
why wont two tables merge correctly on a date?
I have one table with a field called 'date' "2009-01-01
00:00:00".
The other table also has a field call 'date'.
The dates are something like ?"2009-01-01 01:00:00".
The two tables are not merging correctly. The dates are not lining up.
<NA>
The table also has other fields with dates in them.
Sorry the data set is very big so I have not loaded it.
The code I'm using to merge is m2 <- merge(m1 ,mt,all=TRUE)