I am working with a time series that looks something like this:

# making a df with POSIXct datetime sequence with just minutes 

#Make reproducible data frame:
set.seed(1234)

datetime <- rep(lubridate::ymd_hm("2016-08-01 15:10"), 60)

# Generate measured value
value <- runif(n = 60, min = 280, max = 1000)

df <- data.frame(datetime, value)

The data is actually recorded at 1 second intervals, but it appears as 60 rows with the same hour and minute with with seconds part always at 00. I want to change it such that each minute has its seconds value increasing at one second intervals. The actual dataset includes many hours of data. Thank you

CodePudding user response：

We can use

df$datetime <- with(df, datetime   seconds(seq_along(datetime)) -1)