How do I change the range of the x-axis with datetimes in matplotlib?

I'm trying to plot a graph of dates on the x-axis and values on the y-axis. It works fine, except that I can't get the range of the x-axis to be appropriate. The x-axis range is always Jan 2012 to Jan 2016, despite my dates being from today. I am even specifying that xlim should be the first and last date.

I'm writing this for python-django, if that's relevant.

 import datetime import matplotlib.pyplot as plt x = [datetime.date(2014, 1, 29), datetime.date(2014, 1, 29), datetime.date(2014, 1, 29)] y = [2, 4, 1] fig, ax = plt.subplots() ax.plot_date(x, y) ax.set_xlim([x[0], x[-1]]) canvas = FigureCanvas(plt.figure(1)) response = HttpResponse(content_type='image/png') canvas.print_png(response) return response 

And here is the output:

2 Answers

Edit:

Having seen actual data from the OP, all of the values are at the same date/time. So matplotlib is automatically zooming the x-axis out. You can still manually set the x-axis limits with datetime objects

If I do something like this on matplotlib v1.3.1:

import datetime import matplotlib.pyplot as plt x = [datetime.date(2014, 1, 29)] * 3 y = [2, 4, 1] fig, ax = plt.subplots() ax.plot_date(x, y, markerfacecolor='CornflowerBlue', markeredgecolor='white') fig.autofmt_xdate() ax.set_xlim([datetime.date(2014, 1, 26), datetime.date(2014, 2, 1)]) ax.set_ylim([0, 5]) 

I get:

And the axes limits match the dates that I specified.

With help from Paul H's solution, I was able to change the range of my time-based x-axis.

Here is a more general solution for other beginners.

import matplotlib.pyplot as plt import datetime as dt # Set X range. Using left and right variables makes it easy to change the range. # left = dt.date(2020, 3, 15) right = dt.date(2020, 7, 15) # Create scatter plot of Positive Cases # plt.scatter( x, y, c="blue", edgecolor="black", linewidths=1, marker = "o", alpha = 0.8, label="Total Positive Tested" ) # Format the date into months & days plt.gca().xaxis.set_major_formatter(mdates.DateFormatter('%m-%d')) # Change the tick interval plt.gca().xaxis.set_major_locator(mdates.DayLocator(interval=30)) # Puts x-axis labels on an angle plt.gca().xaxis.set_tick_params(rotation = 30) # Changes x-axis range plt.gca().set_xbound(left, right) plt.show()