plotting vertical bars instead of points, plot_date
<p>I want to plot vertical bars instead of points.  The actual data I have are irregularly spaced, so this will help visualize gaps more easily.
When I try to plot it, the best I can do are points, which don't increase in size as you zoom in!</p>

<pre><code>import matplotlib
from matplotlib import pyplot as plt
import datetime

XX = [datetime.date.today()+datetime.timedelta(x) for x in range(10)]
YY = range(10)
plt.plot_date(XX,YY,'o')
</code></pre>

<p><a href="http://i.stack.imgur.com/lYheA.png" rel="nofollow"><img src="http://i.stack.imgur.com/lYheA.png" alt="enter image description here"></a></p>

<p><a href="http://i.stack.imgur.com/cGna8.png" rel="nofollow"><img src="http://i.stack.imgur.com/cGna8.png" alt="enter image description here"></a></p>

<p>Any ideas on how I can make taller/bigger (but not wider!) points?</p>

<p>Did you mean bars like this? </p>

<p><a href="http://i.stack.imgur.com/Cb83O.png" rel="nofollow"><img src="http://i.stack.imgur.com/Cb83O.png" alt="enter image description here"></a></p>

<p>And here is the code:</p>

<pre><code>import matplotlib
from matplotlib import pyplot as plt
import datetime

XX = [datetime.date.today()+datetime.timedelta(x) for x in range(10)]
YY = range(10)

plt.plot_date(XX,YY,'|')
plt.show()
</code></pre>

<p>You can change the shape of your plot by changing the third argument you pass in the plt.plot_date function. 
In your code you are passing an 'o' that is why you get a dot. Here i pass bar to plot bar.</p>

python date matplotlib