title: How do I plot just the positive error bar with pyplot.bar?
body: <p>I'm trying to plot 4 average values with positive error bars and the max value within the plot.</p>
  
  <pre><code>means   = [26.82,26.4,61.17,61.55]         # Mean Data 
  stds    = [4.59,4.39,4.37,4.38]            # Standard deviation Data
  peakval = ['26.82','26.4','61.17','61.55'] # String array of means
  
  ind = np.arange(len(means))
  width = 0.35
  colours = ['red','blue','green','yellow']
  
  pyplot.figure()
  pyplot.title('Average Age')
  for i in range(len(means)):
      pyplot.bar(ind[i],means[i],width,color=colours[i],align='center',yerr=stds[i],ecolor='k')
  pyplot.ylabel('Age (years)')
  pyplot.xticks(ind,('Young Male','Young Female','Elderly Male','Elderly Female'))
  
  def autolabel(bars,peakval):
      for ii,bar in enumerate(bars):
          height = bars[ii]
          pyplot.text(ind[ii], height-5, '%s'% (peakval[ii]), ha='center', va='bottom')
  autolabel(means,peakval)    
  </code></pre>
  
  <p>However I can can't find out how to plot only the positive error bars. 
  So I end up with a graph like this:</p>
  
  <p><img src="https://i.stack.imgur.com/JYF6H.png" alt="Average Age"></p>
  
  <p>Any suggestions would be greatly appreciated.</p>