在R中使用半小时数据创建时间序列

Question

This is my first time ever asking a question on Stack Overflow and I'm a programming novice so any advice as to how to improve my question asking abilities would be appreciated.

Onto my question: I have two csv files, one containing three columns (date time in dd/mm/yyyy hh:(00 or 30) format, production of a certain product, and demand for said product), and the other containing several columns (decomposition of the date time into year, month, day, hour, and whether it is :00 or :30 represented by 1 or 2 respectively, alongside several columns for independent variables which may affect production/demand of said product).

I've only played around with the first csv file, converting the string into a datetime object but the ts() function won't recognise the datetime objects as my times. I've tried adjusting the frequency parameter but ultimately failed and have no idea how to create a time series using half hourly data. Would appreciate any help.

Thanks in advance!

Answer 1

My suggestion is to apply the "difftime" over all your time data. For instance, like following code, you can use your initial time (the time of first record) for all comparisons as time_start and the others as time_finish. Then it return the time intervals as number of seconds and then you are ready to use other column values as the value of the time stamps.

interval=as.integer(difftime(strptime(time_finish,"%H:%M"),strptime(time_start,"%H:%M"),units = "sec"))

Second 0 10 15 ....