Hi, I have been following a very good online tutorial for matplotlib:
http://www.loria.fr/~rougier/teaching/matplotlib/#introduction However, when I try to annotate the point where the cosine/sine graphs cross the scatter graph misses the point where it crosses the axes; green and pink colours. Anyone know why and/or what I have done wrong? Help appreciated _______________________CODE BELOW_________________ #the points x = np.linspace(-np.pi, np.pi, 256, endpoint=True) C,S=np.cos(x), np.sin(x) #axis limits xlim(x.min()*1.1, x.max()*1.1) ylim(C.min()*1.1,C.max()*1.1) #spines, there are four (top, bottom, left and right). #spines, remove top and right, and move left and bottom #gca returns current axis instance. Used to control axis properties using either set or "Axes" methods #I assume "gca" stands for Get Current Axis, like "gcf" stands for Get Current Figure ax=gca() #spines ax.spines['right'].set_color('none') ax.spines['top'].set_color('none') #ticks ax.xaxis.set_ticks_position('bottom') ax.yaxis.set_ticks_position('left') #reposition ax.spines['left'].set_position(('data',0)) ax.spines['bottom'].set_position(('data',0)) #ticks ticks as tuples and labels as LaTex tuples. #Note: if these next two lines of code go before the spine changes the labelling is lost xticks([-np.pi,-np.pi/2,0,np.pi/2,np.pi],[r'$-\pi$',r'$-\pi/2$',r'$0$',r'$+\pi/2$',r'$+\pi$']) yticks([-1,0,1],[r'$-1$',r'0',r'$+1$']) #plotting plot(x,C,color="blue", linewidth = 2.5, linestyle="dotted",label = 'Sine') plot(x,S, color="red", linewidth="2.5",linestyle="-.", label='Cosine') #legend. Note remember to add label to plot statement e.g. 'Sine' as the legend requires it #NOTE: legend has to go after plot statement in order to get the graph labels legend(loc='upper left') #Annotation #the green point. NOTE: use the scatter method t=pi/4 scatter([t,],[np.cos(t),],color='green',linewidth=10) #draw the lines with plot plot([t,cos(t)],[t,0],color='green') plot([0,cos(t)],[t,cos(t)],color='pink') scatter([t,],[0,],color='black') scatter([0,],[cos(t),],color='black') show() -- https://mail.python.org/mailman/listinfo/python-list
