Matplotlibで日本語文字化けを解決できる簡単な方法

import numpy as np
import matplotlib.pyplot as plt

rand_array = np.random.randint(10, size=20)

plt.figure(figsize=(10, 6))
plt.plot(rand_array)
plt.title("晴耕雨読")
plt.ylabel("前人未踏")
plt.xlabel("率先垂範")
plt.show()

import matplotlib

# Get font family
print(matplotlib.rcParams["font.family"])
# >> ['sans-serif']

# Get fonts within the family
matplotlib.rcParams["font.sans-serif"]
# >> ['DejaVu Sans', 'Bitstream Vera Sans', 'Computer Modern Sans Serif', 'Lucida Grande', 'Verdana', 'Geneva', 'Lucid', 'Arial', 'Helvetica', 'Avant Garde', 'sans-serif']

import matplotlib
fonts = set([f.name for f in matplotlib.font_manager.fontManager.ttflist])
len(fonts), fonts
# >> (303, {'.Aqua Kana', '.Keyboard', '.New York', '.SF Arabic', '.SF Compact', '.SF Compact Rounded', ...

import matplotlib
# Matplitlib gives warning when a character cannot be plotted with a font
# We need to escalate it to error so that we can catch it
import warnings
warnings.filterwarnings("error")

# Get all fonts in the OS
fonts = set([f.name for f in matplotlib.font_manager.fontManager.ttflist])

# Initialize a list where we'll keep Japanese compatible fonts
jp_compatible_fonts = []

for i, font in enumerate(fonts):
 # Try plotting a text that says: XXフォントが日本語をサポートしているので、大好き！
 # Fonts that don't support Japanese will give error
 try:
  fig  = plt.figure(figsize=(0.5,0.5)) 

  plt.text(0, 0, f"{font}フォントが日本語をサポートしているので、大好き！", fontname=font)
  plt.axis('off')
  plt.draw()
  plt.pause(0.001)
  
  # If successfully plotted, add it to the list
  jp_compatible_fonts.append(font)

 except UserWarning:
  pass
 
 # Close the figure so that incompatible font does not influence the next plot
 plt.close(fig)

jp_compatible_fonts
# >> ['Apple SD Gothic Neo', 'Hiragino Mincho ProN', 'Arial Unicode MS', 'Heiti TC', 'Hiragino Maru Gothic Pro', 'Hiragino Sans GB', 'Hiragino Sans', 'PingFang HK', '.Aqua Kana']

import matplotlib
fig = plt.figure()
for i, font in enumerate(jp_compatible_fonts):
 plt.text(
  0,
  i,
  f"{font}フォントが日本語をサポートしているので、大好き！",
  fontname=font,
 )
    
plt.axis("off")
plt.ylim(0, len(jp_compatible_fonts))
plt.show()

import numpy as np
import matplotlib.pyplot as plt

### CHANGE THE FONT FROM DEFAULT TO HIRAGINO SANS
plt.rcParams['font.family'] = "Hiragino Sans"

rand_array = np.random.randint(10, size=20)

plt.figure(figsize=(10, 6))
plt.plot(rand_array)
plt.title("晴耕雨読")
plt.ylabel("前人未踏")
plt.xlabel("率先垂範")
plt.show()

import matplotlib.pyplot as plt
plt.rcParams['font.family'] = "Hiragino Sans"