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

User · Answer

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.

User · Answer

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  plt plot A B  for xy in zip A  B                                            lt --     ax annotate    s   s     xy  xy xy  textcoords  data      lt --  plt grid   plt show

[python] Label python data points on plot

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