How to get actual data points from a graph using python?

Question

I have made a graph on stock data using fbprophet module in python. my graph looks like this :

The code i m using is this:

model = Prophet()
model.fit(df)
future = model.make_future_dataframe(periods=365)  # forecasting for 1 year from now.
forecast = model.predict(future)

''' Plotting the forecast '''
figure = model.plot(forecast)
plt.plot = figure

figure.savefig('forecasting for 1 year.svg')

From above code i have made that graph. then i extracted the data points from it using mpld3 module

import mpld3
# print(mpld3.fig_to_dict(figure))
print(mpld3.fig_to_dict(figure)['data'])

It gives me output like this:

{'data01': [[734094.0, 3.3773930153824794], [734095.0, 3.379438304627263],  ........ 'data03': [[0.0, 0.0]]}

But the problem is from the above output the y values i m getting is correct but not the x values.. The actual x values are like this :

"x": [
        "2010-11-18 00:00:00",
        "2010-11-19 00:00:00",
        "2010-11-22 00:00:00" ... ]

but i m getting x values like this : 734094.0 , 734095.0 ..

So how can i get the actual data (data points x and y values ) from graph ??

Is there any other way to do it ? I want to extract data points from graph then send those from a flask api to UI (angular 4)

Thanks in advance!

John Ladasky · Accepted Answer · 2018-06-25 07:53:32Z

1

734094 / 365.25 = 2009.8398. That's a very suggestive number for a date that, from your example, I assume is 2010-11-18. It looks like your date information is expressed as a floating-point number, where the difference of 1.0 corresponds to one day: and, the reference date for the value 0.0 is January 1, 1 AD.

You could try to write a function that counts from 01-01-1, or maybe you could find one in a library. Alternately, you could look at the converted value for a date you know, and work from there.

answered Jun 25, 2018 at 7:53

John Ladasky

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5 Comments

Abdullah Ahmed Ghaznavi Over a year ago

I didn't get it. if a have a value 734094.0 how can i extract the correct date from it. and the dates are not fixed dates might be changed depending upon the data..

John Ladasky Over a year ago

OK, I looked a little bit further into your import statements. It appears that mpld3 is a fork of Matplotlib intended for incorporation in web pages. It is no longer actively maintained. If mpld3 is indeed a wrapper around Matplotlib, you are interested in the way that Matplotlib stores information about dates. You will want to read matplotlib.org/api/dates_api.html. (Continued...)

John Ladasky Over a year ago

As I predicted from doing the arithmetic I showed you: "Matplotlib represents dates using floating point numbers specifying the number of days since 0001-01-01 UTC, plus 1." And furthermore, I predicted: "There are a number of helper functions to convert between datetime objects and Matplotlib dates... num2date(): Convert Matplotlib dates to datetime objects."

Abdullah Ahmed Ghaznavi Over a year ago

Thanks a lot for your responses let me check it then i will get back to you!

Abdullah Ahmed Ghaznavi Over a year ago

thanks a lot! it worked! the info you gave me in your comments are very useful thank you for that. that num2date function helped me! :)

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