Two hourly time series xts1 and xts2, xts1 has some missing times.
xts1
time speed power
2010-01-01 00:00:00 0.1 1.1
2010-01-01 01:00:00
Try
library(xts)
xts1 <- xts(df1[-1], order.by = as.POSIXct(df1$time))
xts2 <- xts(df2[-1], order.by = as.POSIXct(df2$time))
res <- xts1+xts2
res[,1] <- res[,1]/2
res
# speed power
#2010-01-01 00:00:00 0.1 2.2
#2010-01-01 01:00:00 0.2 2.4
df1 <- structure(list(time = c("2010-01-01 00:00:00",
"2010-01-01 01:00:00",
"2010-01-01 05:00:00"), speed = c(0.1, 0.2, 0.2), power = c(1.1,
1.2, 1.2)), .Names = c("time", "speed", "power"),
class = "data.frame", row.names = c(NA, -3L))
df2 <- structure(list(time = c("2010-01-01 00:00:00",
"2010-01-01 01:00:00",
"2010-01-01 02:00:00"), speed = c(0.1, 0.2, 0.2), power = c(1.1,
1.2, 1.2)), .Names = c("time", "speed", "power"),
class = "data.frame", row.names = c(NA, -3L))