When I use the errorbar() routine to plot data, unless I set hold=True as a kwarg (or set it globally), the data are plotted without the errorbars. I believe it is because the routine first plots the error bars, then overplots the data points and for some reason the routine is clearing the axis in between these steps.
This is rather annoying for interactive use and does not seem to be the expected behavior. For example, if I run the example code from the errorbar page (my copy pasted below), I get a nice plot of the data with no error bars. This seems to be the effect either from within "ipython -pylab" or from standalone scripts.
Any advice would be greatly appreciated, thanks.
import numpy as np
import matplotlib.pyplot as plt
# example data
x = np.arange(0.1, 4, 0.5)
y = np.exp(-x)
# example variable error bar values
yerr = 0.1 + 0.2*np.sqrt(x)
xerr = 0.1 + yerr
# First illustrate basic pyplot interface, using defaults where possible.
plt.errorbar(x, y, xerr=0.2, yerr=0.4)
plt.title("Simplest errorbars, 0.2 in x, 0.4 in y")