Confusion Matrix in Python

Plot a pretty confusion matrix (like Matlab) in python using seaborn and matplotlib

Created on Mon Jun 25 14:17:37 2018 @author: Wagner Cipriano - wagnerbhbr

This module get a pretty print confusion matrix from a NumPy matrix or from 2 NumPy arrays (y_test and predictions).

Installation

pip install pretty-confusion-matrix

Get Started

Examples:

import numpy as np
import pandas as pd
from pretty_confusion_matrix import pp_matrix

array = np.array([[13,  0,  1,  0,  2,  0],
                  [0, 50,  2,  0, 10,  0],
                  [0, 13, 16,  0,  0,  3],
                  [0,  0,  0, 13,  1,  0],
                  [0, 40,  0,  1, 15,  0],
                  [0,  0,  0,  0,  0, 20]])

# get pandas dataframe
df_cm = pd.DataFrame(array, index=range(1, 7), columns=range(1, 7))
# colormap: see this and choose your more dear
cmap = 'PuRd'
pp_matrix(df_cm, cmap=cmap)

import numpy as np
from pretty_confusion_matrix import pp_matrix_from_data

y_test = np.array([1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2,
                  3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5])
predic = np.array([1, 2, 4, 3, 5, 1, 2, 4, 3, 5, 1, 2, 3, 4, 4, 1, 4, 3, 4, 5, 1, 2, 4, 4, 5, 1, 2, 4, 4, 5, 1, 2, 4, 4, 5, 1, 2, 4, 4, 5, 1, 2, 3, 3, 5, 1, 2, 3, 3, 5, 1, 2,
                  3, 4, 4, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2, 3, 4, 1, 1, 2, 4, 4, 5, 1, 2, 4, 4, 5, 1, 2, 4, 4, 5, 1, 2, 4, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5, 1, 2, 3, 4, 5])

pp_matrix_from_data(y_test, predic)

References:

1. Mat lab confusion matrix

   https://www.mathworks.com/help/nnet/ref/plotconfusion.html

   https://www.mathworks.com/help/examples/nnet/win64/PlotConfusionMatrixUsingCategoricalLabelsExample_02.png

   https://stackoverflow.com/questions/5821125/how-to-plot-confusion-matrix-with-string-axis-rather-than-integer-in-python/51176855#51176855

2. Other Examples in python

a) https://stackoverflow.com/a/51176855/1809554

b) https://www.programcreek.com/python/example/96197/seaborn.heatmap

c) http://scikit-learn.org/stable/auto_examples/model_selection/plot_confusion_matrix.html#sphx-glr-auto-examples-model-selection-plot-confusion-matrix-py