On Tuesday, November 26, 2013 7:34:31 PM UTC, EricGarlic wrote: > Correction: I meant Plot not Scatter - corrected below. Issue is with Plot statement
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 plot 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
