text: #!/usr/bin/env python
  from pylab import *
  
  t = arange(0.1, 4, 0.1)
  s = exp(-t)
  e = 0.1*abs(randn(len(s)))
  f = 0.1*abs(randn(len(s)))
  g = 2*e
  h = 2*f
  
  figure()
  errorbar(t, s, e, fmt='o')             # vertical symmetric
  
  figure()
  errorbar(t, s, None, f, fmt='o')       # horizontal symmetric
  
  figure()
  errorbar(t, s, e, f, fmt='o')          # both symmetric
  
  figure()
  errorbar(t, s, [e,g], [f,h], fmt='--o')  # both asymmetric
  
  figure()
  errorbar(t, s, [e,g], f, fmt='o', ecolor='g')      # both mixed
  
  figure()
  errorbar(t, s, e, [f,h], fmt='o')      # both mixed
  
  figure()
  errorbar(t, s, [e,g], fmt='o')         # vertical asymmetric
  
  figure()
  errorbar(t, s, yerr=e, fmt='o')        # named
  
  figure()
  errorbar(t, s, xerr=f, fmt='o')        # named
  xlabel('Distance (m)')
  ylabel('Height (m)')
  title('Mean and standard error as a function of distance')
  
  figure()
  ax = subplot(111)
  ax.set_yscale('log')
  errorbar(t, s+2, e, f, fmt='o')          # both symmetric
  
  #savefig('errorbar_demo')
  show()
  