text: from pylab import *
  from matplotlib.collections import LineCollection
  
  # In order to efficiently plot many lines in a single set of axes,
  # Matplotlib has the ability to add the lines all at once. Here is a
  # simple example showing how it is done.
  
  N = 50
  x = arange(N)
  # Here are many sets of y to plot vs x
  ys = [x+i for i in x]
  
  # We need to set the plot limits, they will not autoscale
  ax = axes()
  ax.set_xlim((amin(x),amax(x)))
  ax.set_ylim((amin(amin(ys)),amax(amax(ys))))
  
  # colors is sequence of rgba tuples
  # linestyle is a string or dash tuple. Legal string values are
  #          solid|dashed|dashdot|dotted.  The dash tuple is (offset, onoffseq)
  #          where onoffseq is an even length tuple of on and off ink in points.
  #          If linestyle is omitted, 'solid' is used
  # See matplotlib.collections.LineCollection for more information
  line_segments = LineCollection([list(zip(x,y)) for y in ys], # Make a sequence of x,y pairs
                                  linewidths=(0.5,1,1.5,2),
                                  linestyles = 'solid')
  line_segments.set_array(x)
  ax.add_collection(line_segments)
  fig = gcf()
  axcb = fig.colorbar(line_segments)
  axcb.set_label('Line Number')
  ax.set_title('Line Collection with mapped colors')
  sci(line_segments) # This allows interactive changing of the colormap.
  show()
  