CODEWITHSUNDEEP
matplotlib
jul
jul

Reputation: 37464

How can I draw single points on a plot already containing data?

In a while loop I'm updating two sets of data in a plot (some data X and a threshold). Now I'd like to add single points (peaks of X) on the same plot. How can I do that?

import matplotlib.pyplot as plt

plt.ion()

fig = plt.figure()

plt_ps = fig.add_subplot(111)

# initialize plots
powerspectrum, = plt_ps.plot(np.zeros([windowSize,]))
threshold, = plt_ps.plot(np.zeros([windowSize,]))
peaks, = plt_ps.plot([], [], 'or') # peaks will just be a set of coordinates, eg peaks_x=[2,4,7] and peaks_y=[3,7,6]

while(somecondition):

    # some data processing

    powerspectrum.set_ydata(new_powerspectrum_data)
    threshold.set_ydata(new_threshold_data)
    #peaks.? how do I set new peaks? Tried peaks.set_data(peaks_x, peaks_y) but peaks do not show up
    plt_ps.relim()
    plt_ps.autoscale_view()
    fig.canvas.draw()

Upvotes: 1

Views: 105

Answers (1)

Alvaro Fuentes
Alvaro Fuentes

Reputation: 17455

Just use plot with the right style:

import matplotlib.pyplot as plt

xs = [1,2,5,3,6,7,1,3,4,5,2,6,7,8,2,1]
ys = [3,4,5,2,7,1,3,4,1,2,3,4,5,2,3,1]

plt.plot(xs,ys,'.')
plt.show()

Upvotes: 1

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