Is there an 'empty' patch in matplotlib?

Question

I am adding patches according to a list of ones and zeros (e.g. [1, 0, 1, 1, 0, 0, 1, 0, 1, 0]). I want to add patches where there are ones using matplotlib and leave the zeros empty. However, trying the following code raises a list index out of range error:

fig = plt.figure()
ax = plt.axes()
self.patches = []
for i, val in enumerate(my_list):
    if val == 1:
        self.patches.append(plt.Rectangle((i, 0), 0.9, 1, angle=0.0,
                                          facecolor='r', edgecolor='w',
                                          linewidth='2.0',
                                          animated=False))
    ax.add_patch(self.patches[i])

The only thing I can think of is using an else statement in the code above to add a rectangle with the same colour as the background for the zeros. Is there an empty patch object that one could use instead? I want the patches to be in the same position as the ones in the list.

Diziet Asahi · Accepted Answer · 2020-10-19 15:04:54Z

1

use color='none' to set all colors (facecolor and edgecolor to invisible).

alternatively, you can pass visible=False to the constructor to hide the patch.

Your loop could be:

my_list = [1, 0, 1, 1, 0, 0, 1, 0, 1, 0]
patches = []
fig, ax = plt.subplots()
for i, val in enumerate(my_list):
    p = plt.Rectangle((i, 0), 0.9, 1, angle=0.0,
                                          facecolor='r', edgecolor='w',
                                          linewidth='2.0',
                                          animated=False, visible=bool(val))
    patches.append(p)
    ax.add_patch(p)

edited Oct 19, 2020 at 15:04

answered Oct 19, 2020 at 13:46

Diziet Asahi

41k8 gold badges67 silver badges85 bronze badges

Sign up to request clarification or add additional context in comments.

2 Comments

DJTS Over a year ago

Should it be visible=bool(val) in the Rectangle options? I think if you use the index value it would give true for all but the first index, but we want true/false for 1/0 in list.

Diziet Asahi Over a year ago

yes, of course, sorry wasn't paying enough attention. Updated answer.

Jody Klymak · Accepted Answer · 2020-10-19 14:44:50Z

1

Sure, you can pass an empty patch to Matplotlib, but I wouldn't unless for some reason you want matplotlib to know about your missing data:

fig = plt.figure()
ax = plt.axes()
self.patches = []
for i, val in enumerate(my_list):
    if val == 1:
        self.patches.append(plt.Rectangle((i, 0), 0.9, 1, angle=0.0,
                                          facecolor='r', edgecolor='w',
                                          linewidth='2.0',
                                          animated=False))
        ax.add_patch(self.patches[i])
    else:
        self.patches.append(None)

answered Oct 19, 2020 at 14:44

Jody Klymak

6,1572 gold badges20 silver badges37 bronze badges

2 Comments

DJTS Over a year ago

If, for example, I was animating these patches with FuncAnimation, updating the list with new positions for the ones, would matplotlib need to know about the missing data (i.e. the zeros). Would this be a good case for appending None?

Jody Klymak Over a year ago

Sure thats a reason. OTOH, you'll need to also toggle visibility.

Collectives™ on Stack Overflow

Is there an 'empty' patch in matplotlib?

2 Answers 2

2 Comments

2 Comments

Your Answer

Hot Network Questions

Collectives™ on Stack Overflow

2 Answers 2

2 Comments

2 Comments

Your Answer

Sign up or log in

Post as a guest

Related