I have the following code:
import numpy as np import matplotlib.pyplot as plt x = np.random.rand(5) y = np.random.rand(5) markerfacecolors = ['k','k','none','k','k'] plt.plot(x,y,'--o',markerfacecolor=markerfacecolors)
I tried the above and got the following error-
ValueError: RGBA sequence should have length 3 or 4
How do I resolve this ? or is there an alternative solution to the problem ( rather than splitting into multiple figures)?
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Answer
If you read the documentation associated to plt.plot, if you will see that the only properties affecting markers are:
marker: marker style string markeredgecolor or mec: color markeredgewidth or mew: float markerfacecolor or mfc: color markerfacecoloralt or mfcalt: color markersize or ms: float markevery: None or int or (int, int) or slice or list[int] or float or (float, float) or list[bool]
By looking at them, it appears that there are no way to set custom style to a single or a few selected markers. Note one of your errors, where you used markerfacecolor=markerfacecolors. However, markerfacecolor needs to be a color (either a string, or an tuple (R, G, B)), not multiple colors.
One way to get around this design choice is using multiple plot commands, masking the interested value/s. For example:
import numpy as np import matplotlib.pyplot as plt import matplotlib.cm as cm x = np.random.rand(5) y = np.random.rand(5) mask1 = np.ones_like(x, dtype=bool) mask1[3] = False mask2 = np.logical_not(mask1) # Matplotlib uses Tab10 as default colorloop. # Need to use the same color for each plot command color = cm.tab10.colors[0] plt.figure() plt.plot(x,y,'--') plt.plot(np.ma.masked_array(x, mask2),y,'o', color=color) plt.plot(np.ma.masked_array(x, mask1),y,'o', color=color, markerfacecolor='none')