Matplotlib date and time graph

Question

The plot_date pyplot function expects pairs of dates and values ​​to be built with a specific line style. Is there a recommended approach for plotting multiple values ​​or interval data from date / time values?

Answer 1

To plot interval data, you can use the error panel provided by the <strong> function and use axis.xaxis_date () errorbar () to make Matplotlib format the axes, as the plot_date () function does.

Here is an example:

#!/usr/bin/python import datetime import numpy as np import matplotlib.dates as mdates import matplotlib.pyplot as plt # dates for xaxis event_date = [datetime.datetime(2008, 12, 3), datetime.datetime(2009, 1, 5), datetime.datetime(2009, 2, 3)] # base date for yaxis can be anything, since information is in the time anydate = datetime.date(2001,1,1) # event times event_start = [datetime.time(20, 12), datetime.time(12, 15), datetime.time(8, 1,)] event_finish = [datetime.time(23, 56), datetime.time(16, 5), datetime.time(18, 34)] # translate times and dates lists into matplotlib date format numpy arrays start = np.fromiter((mdates.date2num(datetime.datetime.combine(anydate, event)) for event in event_start), dtype = 'float', count = len(event_start)) finish = np.fromiter((mdates.date2num(datetime.datetime.combine(anydate, event)) for event in event_finish), dtype = 'float', count = len(event_finish)) date = mdates.date2num(event_date) # calculate events durations duration = finish - start fig = plt.figure() ax = fig.add_subplot(1, 1, 1) # use errorbar to represent event duration ax.errorbar(date, start, [np.zeros(len(duration)), duration], linestyle = '') # make matplotlib treat both axis as times ax.xaxis_date() ax.yaxis_date() plt.show()