Matplotlib Markers
Markers let you highlight individual data points on a Matplotlib line or scatter plot.
Adding markers to a plot
By default, plt.plot() draws only a connecting line with no visible dots at each data point. Passing the marker keyword argument tells Matplotlib to draw a small symbol at every (x, y) pair, which is useful when the underlying data points themselves matter, not just the trend between them.
Example
import matplotlib.pyplot as plt
days = [1, 2, 3, 4, 5]
temps = [15, 18, 17, 21, 19]
plt.plot(days, temps, marker="o")
plt.show()Marker reference
The fmt shorthand string
Marker, line style, and color can all be combined into a single short string, sometimes called the fmt (format) string, passed as the third positional argument to plt.plot(). The pattern is marker, then line style, then color, and any of the three can be left out.
Example
import matplotlib.pyplot as plt
x = [1, 2, 3, 4, 5]
y = [2, 4, 3, 6, 5]
plt.plot(x, y, "o--r")
plt.show()Customizing marker size and color
Beyond the shape, you can control a marker's size with markersize (or the shorthand ms), the outline color with markeredgecolor (mec), and the fill color with markerfacecolor (mfc).
Example
import matplotlib.pyplot as plt
x = [1, 2, 3, 4, 5]
y = [5, 7, 6, 9, 8]
plt.plot(x, y, marker="o", ms=12, mec="black", mfc="gold")
plt.show()
