8
$\begingroup$

Bug introduced in 9.0.0 and fixed in 9.0.1

Quantity is new in 9.0.0

Is there a way to use DateListPlot with Quantity values? I retrieved the following time series data from WolframAlpha:

gasPrices = WolframAlpha[
"us gas prices", {{"History:Price:GasPriceData", 1}, 
"TimeSeriesData"}];

Each data point is composed of a date and a Quantity:

{{{1993, 4, 5, 0, 0, 0.}, Quantity[1.068, ("USDollars")/("Gallons")]},
 {{1993, 4, 19, 0, 0, 0.}, Quantity[1.079, ("USDollars")/("Gallons")]},
...
 {{2012, 12, 31, 0, 0, 0.}, Quantity[3.369, ("USDollars")/("Gallons")]} }

I can plot the values using ListPlot:

 ListPlot[gasPrices[[All,2]]]

enter image description here

Strangely however, DateListPlot produces an empty plot:

 DateListPlot[gasPrices]

Empty plot from DateListPlot

To get DateListPlot to produce a proper plot I have to do this instead:

DateListPlot[ Transpose[{gasPrices[[All, 1]], gasPrices[[All, 2, 1]]}] ]

OK plot from DateListPlot

Am I missing something? I would have thought that Quantity values could be taken directly by DateListPlot, as they are by ListPlot.

Improve this question
$\endgroup$
2
  • $\begingroup$ I tested your code and it seems that Units are not properly implemented in DateListPlot $\endgroup$
    – Murta
    Jan 5 '13 at 18:36
  • $\begingroup$ You can also do: DateListPlot[QuantityMagnitude[gasPrices]] to remove the units. $\endgroup$
    – ecoxlinux
    Jan 15 '13 at 5:23
4
$\begingroup$

This appears to work in the 9.0.1 release:

 DateListPlot[gasPrices]

enter image description here

Improve this answer
$\endgroup$
0

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.