When creating a plot that should be modified later, we need references to a figure and an axes object. For this, we have to create a figure first and then define some axes and their location in the figure, and we should not forget to assign these objects to a variable:
fig = figure() ax = subplot(111)
A figure can have several axes objects depending on the use of subplot. In a second step, plots are associated with a given axes object:
fig = figure(1)
ax = subplot(111)
x = linspace(0,2*pi,100) # We set up a function that modulates the
# amplitude of the sin function
amod_sin = lambda x: (1.-0.1*sin(25*x))*sin(x)
# and plot both...
ax.plot(x,sin(x),label = 'sin')
ax.plot(x, amod_sin(x), label = 'modsin')
Here, we used an anonymous function indicated by the keyword lambda. We will explain this construct later in Section 7.7, Anonymous functions. In fact, these two plot commands fill the list...
