[R] Merging on Datetime Column

[vioravis]

I have the following dataframe with the first column being of type datetime:

dateTime <- c("10/01/2005 0:00",
              "10/01/2005 0:20",
              "10/01/2005 0:40",
              "10/01/2005 1:00",
              "10/01/2005 1:20")
var1 <- c(1,2,3,4,5)
var2 <- c(10,20,30,40,50)
df <- data.frame(dateTime = dateTime, var1 = var1, var2 = var2)
df$dateTime <- strptime(df$dateTime,"%m/%d/%Y %H:%M")

I want to create 10 minute interval data as follows:

minTime <- min(df$dateTime)
maxTime <- max(df$dateTime)
newTime <- seq(minTime,maxTime,600)
newDf <- data.frame(newDateTime = newTime)
newDf <- merge(newDf,df,by.x = "newDateTime",by.y = "dateTime",all.x = TRUE)

The objective here is to create a data frame with values from df for the
datetime in df and NA for the missing ones. However, I am getting the
following data frame with both Var1 and Var2 having all NAs.

> newDf
          newDateTime var1 var2
1 2005-10-01 00:00:00   NA   NA
2 2005-10-01 00:10:00   NA   NA
3 2005-10-01 00:20:00   NA   NA
4 2005-10-01 00:30:00   NA   NA
5 2005-10-01 00:40:00   NA   NA
6 2005-10-01 00:50:00   NA   NA
7 2005-10-01 01:00:00   NA   NA
8 2005-10-01 01:10:00   NA   NA
9 2005-10-01 01:20:00   NA   NA

Can someone help me on how to do the merge based on the two datetime
columns?

Thank you.

Ravi






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