#Python code shown below
#This code is issued under the Creative Commons CC0 "License"

from pylab import *

#Arbitrary values that result in a good illustrative example    
data = array([1,3,4,5,8,8.5,9,10.5,11])
weights = array([0.24, 0.60, 0.33,0.28, 0.2, 0.39, 0.2, 0.1, 0.18])

bar_spacing = 0.02 #Distance between adjacent bars

#Non-medians are blue and the median is red
colors  = ['b','b','b','b','r','b','b','b','b']
colorsw = ['b','b','b','r','b','b','b','b','b']

#normalize the weights, only needed to get the two plots to line up
weights = weights / sum(weights)
unweights = ones(data.__len__())/data.__len__() #Equal weighting

#The locations start at zero and are spaced by the width
locations = concatenate((array([0]),cumsum(bar_spacing + unweights[:-1])))
locations_w = concatenate((array([0]),cumsum(bar_spacing + weights[:-1])))

figure()

subplot(2,1,1)
bar(locations, data, width=unweights, color = colors)
ylabel('Value')
tick_params(axis='x', which='both',bottom='off',top='off',labelbottom='off')
xlim([-0.02, sum(unweights+0.02)])
grid()
xticks([])

subplot(2,1,2)
bar(locations_w, data, width=weights, color = colorsw)
ylabel('Value')
tick_params(axis='x', which='both',bottom='off',top='off',labelbottom='off')
xlim([-0.02, sum(weights+0.02)])
grid()
xticks([])