CODEWITHSUNDEEP
pythongraphmatplotlib
Toshiro
Toshiro

Reputation: 345

Matplotlib datetime on the x axis

If you have datetime objects on your x-axis how can you get which one was clicked on the click event handler for matplotlib?

I.e when you do this:

def onclick2(event):
    print event.x

onClickId = figure.canvas.mpl_connect('button_press_event', OnClick2)

I've tried event.x, event.xdata and event._x and they all return ints

Upvotes: 4

Views: 2352

Answers (3)

Sardathrion - against SE abuse
Sardathrion - against SE abuse

Reputation: 18246

You should use num2date(…) to get the date back. See this answer for an example of how to use it.

Upvotes: 0

Guy
Guy

Reputation: 318

I came across a similar problem when trying to return timestamp x axis data from a pandas time-indexed data frame plotted using matplotlib. Attempting Ajean's num2date suggestion on event.xdata returns a float value that is far too large to be a date number (e.g. 23286385.16 for 2014-4-14 2:25).

To expand upon Ajean's suggestion, it is best to first convert the datetime object to a numpy.float64 using the matplotlib.dates.date2num function. Then you may use the numpy.float64 array this created as the x-axis with the matplotlib event handler. Returned event.xdata from the event handler may then be converted back to a datetime using matplotlib.dates.num2date function.

Upvotes: 1

Ajean
Ajean

Reputation: 5659

They probably really are ints ... I believe that matplotlib plots dates by converting them to ints or floats first. Try the num2date function in the matplotlib dates module with your event data, that may yield what you want.

Upvotes: 2

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