.. _pylab_examples-line_collection2:

pylab_examples example code: line_collection2.py
================================================



.. plot:: /home/mandrake/rpm/BUILD/matplotlib-1.1.1/doc/mpl_examples/pylab_examples/line_collection2.py

::

    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([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()
    

Keywords: python, matplotlib, pylab, example, codex (see :ref:`how-to-search-examples`)