Plot marker based on other value

I am doing a fairly basic plot plot(ydata) but would like to condition the marker on another array, for example if I have ydata and markerdata then for markerdata > 0 use use a ‘+’ and for markerdata <0 use a ‘-’ and for markerdata = 0 ‘.’

How do I do this?

Vincent Davis
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This is my solution. The main idea is based on using numpy array masking.

import numpy as np
import matplotlib.pyplot as plt

x = np.arange(100)

a = np.arange(-50,50)
plt.plot(x[a>0], a[a>0], “+”)
plt.plot(x[a==0], a[a==0], “.”)
plt.plot(x[a<0], a[a<0], “–”)
plt.show()

···

On Wed, Mar 17, 2010 at 9:29 PM, Vincent Davis <vincent@…3029…> wrote:

I am doing a fairly basic plot plot(ydata) but would like to condition the marker on another array, for example if I have ydata and markerdata then for markerdata > 0 use use a ‘+’ and for markerdata <0 use a ‘-’ and for markerdata = 0 ‘.’

How do I do this?

Gökhan