Japanize Matplotlib

1.1.3 · maintenance · verified Thu Apr 16

Japanize Matplotlib (version 1.1.3) is a Python library that automatically configures Matplotlib to display Japanese fonts correctly. It simplifies the process of handling Japanese text in plots by applying a default font (IPAexGothic) to Matplotlib's settings upon import. The library is currently in maintenance mode, with the last major update in October 2020.

Common errors

```
import japanize_matplotlib したのに日本語表示になりません
```
cause Another plotting library or custom Matplotlib configuration overwrites the font settings applied by `japanize_matplotlib` after its import.

fix Move `import japanize_matplotlib` to be the last import statement related to plotting, or call `japanize_matplotlib.japanize()` after any code that might modify font settings (e.g., `sns.set()`).
```
PackagesNotFoundError: The following packages are not available from current channels: - japanize-matplotlib
```
cause The `japanize-matplotlib` package, especially for certain OS/architectures (e.g., Windows), might not be available in the specified Conda channel.

fix If encountering this with Conda, try installing via pip: `pip install japanize-matplotlib`. This is often a reliable fallback for packages not fully supported across all Conda environments.

Warnings

gotcha Importing `japanize_matplotlib` might be ineffective if other plotting libraries (e.g., Seaborn) are initialized afterward and override Matplotlib's font settings.
Fix: Ensure `import japanize_matplotlib` occurs *after* other plotting library initializations (e.g., `sns.set()`), or explicitly call `japanize_matplotlib.japanize()` after such calls. Alternatively, configure the other library to use 'IPAexGothic' font directly (e.g., `sns.set(font='IPAexGothic')`).
gotcha Linters or code formatters may remove the `import japanize_matplotlib` line if they deem it unused, as its effect is side-dependent.
Fix: To prevent removal, add a `# noqa: F401` comment to the import line (e.g., `import japanize_matplotlib # noqa: F401`) or explicitly call `japanize_matplotlib.japanize()` in your code.

Install

pip install japanize-matplotlib PyPI
conda install -c uehara1414 japanize-matplotlib Conda (uehara1414 channel)

Imports

japanize_matplotlib
```
import japanize_matplotlib
```

Quickstart

Import `japanize_matplotlib` after `matplotlib.pyplot` to automatically configure Japanese font display. Then, create your plots as usual, and Japanese text will be rendered correctly.

import matplotlib.pyplot as plt
import japanize_matplotlib

plt.plot([1, 2, 3, 4])
plt.xlabel('簡単なグラフ (Simple Graph)')
plt.ylabel('値 (Value)')
plt.title('日本語タイトル (Japanese Title)')
plt.grid(True)
plt.show()

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