Label python data points on plot

Question

I searched for ages (hours which is like ages) to find the answer to a really annoying (seemingly basic) problem, and because I cant find a question that quite fits the answer I am posting a question and answering it in the hope that it will save someone else the huge amount of time I just spent on my noobie plotting skills.

If you want to label your plot points using python matplotlib

from matplotlib import pyplot as plt  fig = plt.figure() ax = fig.add_subplot(111)  A = anyarray B = anyotherarray  plt.plot(A,B) for i,j in zip(A,B):     ax.annotate('%s)' %j, xy=(i,j), xytext=(30,0), textcoords='offset points')     ax.annotate('(%s,' %i, xy=(i,j))  plt.grid() plt.show() 

I know that xytext=(30,0) goes along with the textcoords, you use those 30,0 values to position the data label point, so its on the 0 y axis and 30 over on the x axis on its own little area.

You need both the lines plotting i and j otherwise you only plot x or y data label.

You get something like this out (note the labels only):

Its not ideal, there is still some overlap - but its better than nothing which is what I had..

Answer 1

How about print (x, y) at once.

from matplotlib import pyplot as plt  fig = plt.figure() ax = fig.add_subplot(111)  A = -0.75, -0.25, 0, 0.25, 0.5, 0.75, 1.0 B = 0.73, 0.97, 1.0, 0.97, 0.88, 0.73, 0.54  ax.plot(A,B) for xy in zip(A, B):                                       # <--     ax.annotate('(%s, %s)' % xy, xy=xy, textcoords='data') # <--  ax.grid() plt.show() 

Answer 2

I had a similar issue and ended up with this:

For me this has the advantage that data and annotation are not overlapping.

from matplotlib import pyplot as plt import numpy as np  fig = plt.figure() ax = fig.add_subplot(111)  A = -0.75, -0.25, 0, 0.25, 0.5, 0.75, 1.0 B = 0.73, 0.97, 1.0, 0.97, 0.88, 0.73, 0.54  plt.plot(A,B)  # annotations at the side (ordered by B values) x0,x1=ax.get_xlim() y0,y1=ax.get_ylim() for ii, ind in enumerate(np.argsort(B)):     x = A[ind]     y = B[ind]     xPos = x1 + .02 * (x1 - x0)     yPos = y0 + ii * (y1 - y0)/(len(B) - 1)     ax.annotate('',#label,           xy=(x, y), xycoords='data',           xytext=(xPos, yPos), textcoords='data',           arrowprops=dict(                           connectionstyle="arc3,rad=0.",                           shrinkA=0, shrinkB=10,                           arrowstyle= '-|>', ls= '-', linewidth=2                           ),           va='bottom', ha='left', zorder=19           )     ax.text(xPos + .01 * (x1 - x0), yPos,             '({:.2f}, {:.2f})'.format(x,y),             transform=ax.transData, va='center')  plt.grid() plt.show() 

Using the text argument in .annotate ended up with unfavorable text positions. Drawing lines between a legend and the data points is a mess, as the location of the legend is hard to address.