.. _widgets-buttons:

widgets example code: buttons.py
================================

[`source code <buttons.py>`_]

::

    
    import numpy as np
    import matplotlib.pyplot as plt
    from matplotlib.widgets import Button
    
    freqs = np.arange(2, 20, 3)
    
    fig, ax = plt.subplots()
    plt.subplots_adjust(bottom=0.2)
    t = np.arange(0.0, 1.0, 0.001)
    s = np.sin(2*np.pi*freqs[0]*t)
    l, = plt.plot(t, s, lw=2)
    
    
    class Index(object):
        ind = 0
    
        def next(self, event):
            self.ind += 1
            i = self.ind % len(freqs)
            ydata = np.sin(2*np.pi*freqs[i]*t)
            l.set_ydata(ydata)
            plt.draw()
    
        def prev(self, event):
            self.ind -= 1
            i = self.ind % len(freqs)
            ydata = np.sin(2*np.pi*freqs[i]*t)
            l.set_ydata(ydata)
            plt.draw()
    
    callback = Index()
    axprev = plt.axes([0.7, 0.05, 0.1, 0.075])
    axnext = plt.axes([0.81, 0.05, 0.1, 0.075])
    bnext = Button(axnext, 'Next')
    bnext.on_clicked(callback.next)
    bprev = Button(axprev, 'Previous')
    bprev.on_clicked(callback.prev)
    
    plt.show()
    

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