NameError：名称“matplotlib”未在 Python 中定义

NameError: name ‘matplotlib’ is not defined in Python

当我们使用matplotlib模块而不先导入它时，会出现 Python“NameError: name ‘matplotlib’ is not defined”。要解决该错误，请安装模块并在使用前导入它。

nameerror 名称 matplotlib 未定义

在项目的根目录中打开终端并安装matplotlib
模块。

壳


# 👇️ in a virtual environment or using Python 2
pip install matplotlib

# 👇️ for python 3 (could also be pip3.10 depending on your version)
pip3 install matplotlib

# 👇️ if you get permissions error
sudo pip3 install matplotlib

# 👇️ if you don't have pip in your PATH environment variable
python -m pip install matplotlib

# 👇️ for python 3 (could also be pip3.10 depending on your version)
python3 -m pip install matplotlib

# 👇️ alternative for Ubuntu/Debian
sudo apt-get install python3-matplotlib

# 👇️ alternative for CentOS
sudo yum install python3-matplotlib

# 👇️ alternative for Fedora
sudo yum install python3-matplotlib

# 👇️ for Anaconda
conda install -c conda-forge matplotlib

安装matplotlib模块后，确保在使用前导入它。

主程序


# ✅ import matplotlib.pyplot and alias it to plt
import matplotlib.pyplot as plt

# ✅ import matplotlib.image and alias it to pmimg
import matplotlib.image as mpimg


fig, ax = plt.subplots()

print(fig)
print(ax)

img = mpimg.imread('../../doc/_static/stinkbug.png')
print(img)

我们在从matplotlib.

We imported matplotlib.pyplot and aliased it to plt, so you would access any
pyplot methods as plt.plot(), plt.ylabel(), plt.show(), etc.

Make sure you haven’t misspelled the module you are importing because module
names are case-sensitive.

Also, make sure you haven’t imported from matplotlib in a nested scope, e.g. a
function. Import the module at the top level to be able to use it throughout
your code.

Conclusion #

The Python “NameError: name ‘matplotlib’ is not defined” occurs when we use
the matplotlib module without importing it first. To solve the error, install
the module and import it before using it.

–