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: 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>

