Understanding Python Matplotlib Legends and Auxiliary Lines

I have a few questions about Python's matplotlib legend and auxiliary line

Question 1 How do I create a legend for each color?

Question 2 How do I write the interval between the auxiliary lines in increments of 1 for the x, y axes?

Question 3 The interval between the numbers on the scale is 50 and 10 for the x and y axes, respectively, but how do I change the x and y axes to 10 and 5 for each?

I have three questions.

data.txt

 00 0.01619.833
1   0   19.834   52.805
2   0   52.806   84.005
5   0   84.012  107.305
8   0  107.315  128.998
10  0  129.005  138.956
11  0  138.961  145.587
13  0  145.594  163.863
15  0  163.872  192.118
16  0  192.127  193.787
17  0  193.796  197.106
20  0  236.099  246.223
25  1   31.096   56.180
27  1   58.097   64.857
28  1   64.858   66.494
29  1   66.496   89.908
31  1   89.918  111.606
34  1  129.007  137.371
35  1  137.372  145.727
39  1  176.097  209.461
42  1  209.476  226.207
44  1  226.217  259.317
46  1  259.329  282.488
47  1  282.493  298.905

The program is as follows:

#!/usr/bin/env python
# -*-coding:shift_jis-*-
import numpy as np
import matplotlib.pyplot asplt
y,c,x1,x2 = np.loadtxt('data.txt',unpack=True)
color_mapper=np.vectorize(lambdax:{0:'red',1:'blue'}.get(x))

plt.hlines(y, x1, x2, colors=color_mapper(c))
plt.margins (0.1)

plt.grid()
plt.show()

The current graph shows the interval between the numbers on the scale and the interval between the auxiliary lines.
Thank you for your cooperation.

python matplotlib

2022-09-30 14:35

1 Answers

Plot the data separately for each color and label each.

#!/usr/bin/env python
# -*-coding:utf-8-*-

import numpy as np
import matplotlib.pyplot asplt
import matplotlib.ticker as ticker

attributes = {
    0: {
      US>'color': 'red',
      'label': 'label for red'
    },
    1: {
      'color': 'blue',
      'label': 'label for blue'
    }
  }

y,c,x1,x2 = np.loadtxt('data.txt',unpack=True)

for ckey in attributes.keys():
  c_arr=[i for i in range(len(x1))) if c[i]==ckey]
  yy, x_1, x_2 = [y[i] for i in c_arr], [x1[i] for i in c_arr], [x2[i] for i in c_arr]
  plt.hlines(yy, x_1, x_2, colors=attributes[ckey].get('color'), label=attributes[ckey].get('label')))

plt.margins (0.1)
plt.legend(loc='upper left')

## Question 3 How do I change the x and y axes to 10 and 5 respectively?
plt.gca().xaxis.set_major_locator(tick.MultipleLocator(10))
plt.gca().yaxis.set_major_locator(tick.MultipleLocator(5))

## Question 2 How do I write the interval between the auxiliary lines in increments of 1 for the x, y axes?
plt.gca().xaxis.set_minor_locator(tick.MultipleLocator(1)))
plt.gca().yaxis.set_minor_locator(tick.MultipleLocator(1)))
plt.grid(which='both')

plt.show()

2022-09-30 14:35

If you have any answers or tips

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