Prevent axis & column labels from bleeding off heatmap in matplotlib

Question

I'm trying to plot a confusion matrix using the array below. However, when the heatmap renders, the column and axis labels are bleeding off the plot view and I can't figure out how to control this formatting. Seems like I need a way to set some padding values.

import pandas as pd
import matplotlib.pyplot as plt
import seaborn as sn

array = [
    [1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0],
    [0,7,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,1,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,1,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,1],
    [0,0,0,0,3,0,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,2,0,0,0,0,0,0,0,0,0,0,0,1,0,0,2,0,0],
    [0,0,0,0,0,0,3,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0],
    [0,1,0,1,0,0,0,6,0,0,0,0,0,1,0,0,1,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,2,0,0,0,0,0,0,0,0,1,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,3,1,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,1,0,0,0,0,0,1,0,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,5,0,0,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,1,0,0,0,0,0,7,0,0,0,0,0,1,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,3,0,0,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,1,0,0,0,0,0,1,4,1,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,1,0,0,0,0,0,0,0,0,1,0,0,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,5,1,1,0,0,0,0],
    [1,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,38,0,0,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,2,0,0,0,0,0,8,0,0,0,1],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,1,0,0,0,0,1,3,0,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,6,0,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,5,0],
    [0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,0,9]]

labels = ['chatbot',
    'business_passwordreset',
    'business_losthomework',
    'oos_generic',
    'frustration',
    'social_generic',
    'business_accesscode_selfstudy',
    'business_assignmentissues',
    'end_chat',
    'bye',
    'thanks',
    'business_accesscode_lost',
    'business_accesscode_redeem',
    'business_accesscode_notreceived',
    'business_accesscode_share',
    'business_accesscode_reuse',
    'business_editorial',
    'Contact_Request',
    'business_accesscode_error',
    'business_accesscode_refund',
    'hello',
    'business_accesscode_purchase',
    'business_accesscode_troubleshoot']


df_cm = pd.DataFrame(array, index=labels, columns=labels)
sn.heatmap(df_cm, annot=True, cmap='Blues')
plt.show()

Rendered plot:

Everything else looks so good, but would nice to be able to read the labels! Anyone know what I'm missing?

Answer 1

Your labels are really long, so I think your best bet is to create a large figure, and then use plt.tight_layout. As desribed in the docs:

This module provides routines to adjust subplot params so that subplots are nicely fit in the figure

# Create a large figure so your labels aren't too crowded
plt.figure(figsize=(13,7))
df_cm = pd.DataFrame(array, index=labels, columns=labels)
sn.heatmap(df_cm, annot=True, cmap='Blues')
plt.tight_layout()

plt.show()