Change tick frequency on X (time, not number) frequency in matplotlib

Question

My python plot data only show 2 points on x axis.

I would like to have more, but don't know how.

x = [ datetime.datetime(1900,1,1,0,1,2),       datetime.datetime(1900,1,1,0,1,3),       ...       ]                                            # ( more than 1000 elements ) y = [ 34, 33, 23, ............ ]  plt.plot( x, y ) 

The X axis only shows 2 points of interval. I tried to use .xticks but didn't work for X axis. It gave the below error:

TypeError: object of type 'datetime.datetime' has no len() 

Answer 1

Whatever reason it is you are getting 2 ticks only by default, you can fix it (customise it) by changing the ticker locator using a date locator.

import matplotlib.pyplot as plt import matplotlib.dates as mdates  x = [ datetime.datetime(1900,1,1,0,1,2),       datetime.datetime(1900,1,1,0,1,3),       ...       ]                                            # ( more than 1000 elements ) y = [ 34, 33, 23, ............ ]  fig = plt.figure() ax = fig.add_subplot(1,1,1)   plt.plot( x, y )  ax.xaxis.set_major_locator(mdates.MinuteLocator(interval=15))   #to get a tick every 15 minutes ax.xaxis.set_major_formatter(mdates.DateFormatter('%H:%M'))     #optional formatting  

You have several locators (for example: DayLocator, WeekdayLocator, MonthLocator, etc.) read about it in the documentation:

http://matplotlib.org/api/dates_api.html

But maybe this example will help more:

http://matplotlib.org/examples/api/date_demo.html