gg$timestamps <- as.POSIXct(as.character( gg$timestamps ) ) Factors are integers with the appearance of character data, so you are converting the integers to POSIXct. I usually try to avoid letting R automatically convert character data to factors, e.g. using stringsAsFactors=FALSE in read.csv so I don't have to convert them back from factors to manipulate them. -- Sent from my phone. Please excuse my brevity.
On April 27, 2017 9:32:44 PM PDT, Dhivya Narayanasamy <dhiv.shr...@gmail.com> wrote: >Hi Jim, > >Thank you for the reply. 'gg.ts' is actually the object name of the >time >series I am using here. Also I have changed my timestamp class from >factor >to POSIXct (gg$timestamps <- as.POSIXct(gg$timestamps, format = >"%Y-%m-%d >%H-%M-%S") . When i plot this time series on graph, the x axis scales >shows >random value rather than showing timestamp value. Is there any way to >correct the graph to make it show the timestamp value on x axis? I use >plotly function for plotting. > >Regards| Mit freundlichen Grüßen, > >Dhivya Narayanasamy > >Contact No: +91-8438505020 > >On Fri, Apr 28, 2017 at 3:19 AM, Jim Lemon <drjimle...@gmail.com> >wrote: > >> Hi Dhivya, >> I'm not that familiar with the "gg.ts" function, but you are passing >> character values to the "frequency" and "start" arguments. If there >is >> no automatic conversion to numeric values, that would cause the >error. >> Similarly, your "timestamps" variable may have been read in as a >> factor, which often causes trouble with date conversions. Try >> as.character(gg$timestamps) instead of just gg$timestamps. >> >> Jim >> >> >> On Thu, Apr 27, 2017 at 4:51 PM, Dhivya Narayanasamy >> <dhiv.shr...@gmail.com> wrote: >> > Hi, >> > I am new to R. Kindly help me with the plot that gives wrong x-axis >> > values. I have a data frame "gg", that looks like this: >> > >> >> head(gg) >> > >> > timestamps value >> > 1 2017-04-25 16:52:00 -0.4120000 >> > 2 2017-04-25 16:53:00 -0.4526667 >> > 3 2017-04-25 16:54:00 -0.4586667 >> > 4 2017-04-25 16:55:00 -0.4606667 >> > 5 2017-04-25 16:56:00 -0.5053333 >> > 6 2017-04-25 16:57:00 -0.5066667 >> > >> > I need to plot this as a Time series data to do forecasting. The >steps >> are >> > as follows: >> > >> > 1) gg$timestamps <- as.POSIXct(gg$timestamps, format = "%Y-%m-%d >> %H-%M-%S") >> > #changing "Timestamps" column 'factor' to 'as.POSIXct'. >> > >> > 2) gg.ts <- xts(x=gg$value, order.by = gg$timestamps) #converting >the >> > dataframe to time series (Non Regular Time series) >> > >> > 3) fitting <- auto.arima(gg.ts) #fitting the time series model >using >> > auto.arima >> > >> > 4) fore <- forecast(fitting, h=30, level = c(80,95)) #Forecasting >> > >> > 5) I am using plotly to this forecast model (Inspired from here : >> > https://plot.ly/r/graphing-multiple-chart-types/# >> plotting-forecast-objects) >> > >> > plot_ly() %>% >> > add_lines(x = time(gg.ts), y = gg.ts, >> > color = I("black"), name = "observed") %>% >> > add_ribbons(x = time(fore$mean), ymin = fore$lower[, 2], ymax = >> > fore$upper[, 2], >> > color = I("gray95"), name = "95% confidence") %>% >> > add_ribbons(x = time(fore$mean), ymin = fore$lower[, 1], ymax = >> > fore$upper[, 1], >> > color = I("gray80"), name = "80% confidence") %>% >> > add_lines(x = time(fore$mean), y = fore$mean, color = I("blue"), >name = >> > "prediction") >> > >> > >> > The plot comes out wrong: 1) x axis labels are wrong. It shows some >> > irrelevant values on axis. 2) the plot is not coming out. >> > Also I tried to convert "gg.ts" to a regulate time series which >throws >> > error : >> > >> >> gg.xts <- ts(gg.ts, frequency = '1', start = ('2017-04-25 >16:52:00')) >> > Error in 1/frequency : non-numeric argument to binary operator >> > >> > Please help me how to use Date Time values in converting to >regulate time >> > series for forecasting. >> > >> > >> > Regards >> >> Dhivya >> > >> > [[alternative HTML version deleted]] >> > >> > ______________________________________________ >> > R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >> > https://stat.ethz.ch/mailman/listinfo/r-help >> > PLEASE do read the posting guide http://www.R-project.org/ >> posting-guide.html >> > and provide commented, minimal, self-contained, reproducible code. >> > > [[alternative HTML version deleted]] > >______________________________________________ >R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see >https://stat.ethz.ch/mailman/listinfo/r-help >PLEASE do read the posting guide >http://www.R-project.org/posting-guide.html >and provide commented, minimal, self-contained, reproducible code. ______________________________________________ R-help@r-project.org mailing list -- To UNSUBSCRIBE and more, see https://stat.ethz.ch/mailman/listinfo/r-help PLEASE do read the posting guide http://www.R-project.org/posting-guide.html and provide commented, minimal, self-contained, reproducible code.
