Matplotlib Axis Labels and Title

We can use the xlabel() and ylabel() methods to set the labels for the x-axis and y-axis, respectively.

Example

import numpy as np
import matplotlib.pyplot as plt

x = np.array([1, 2, 3, 4])
y = np.array([1, 4, 9, 16])
plt.plot(x, y)

plt.xlabel("x - label")
plt.ylabel("y - label")

plt.show()

The output is displayed as follows:

Title

We can use the title() method to set the title.

Example

import numpy as np
import matplotlib.pyplot as plt

x = np.array([1, 2, 3, 4])
y = np.array([1, 4, 9, 16])
plt.plot(x, y)

plt.title("tutorialpro TEST TITLE")
plt.xlabel("x - label")
plt.ylabel("y - label")

plt.show()

The output is displayed as follows:

Displaying Chinese in Figures

Matplotlib does not support Chinese by default. We can use the following simple method to resolve this.

Here, we use Source Han Sans, a free font developed by Adobe and Google.

Official website: https://source.typekit.com/source-han-serif/cn/

GitHub address: https://github.com/adobe-fonts/source-han-sans/tree/release/OTF/SimplifiedChinese

After opening the link, select one of the fonts:

You can also download from Baidu Netdisk: https://pan.baidu.com/s/10-w1JbXZSnx3Tm6uGpPGOw, extraction code: yxqu.

Download an OTF font, such as SourceHanSansSC-Bold.otf, and place the file in the directory of the executing code file:

Example

import numpy as np 
from matplotlib import pyplot as plt 
import matplotlib

# fname is the path to the font library you downloaded, note the path to SourceHanSansSC-Bold.otf
zhfont1 = matplotlib.font_manager.FontProperties(fname="SourceHanSansSC-Bold.otf") 

x = np.arange(1,11) 
y = 2 * x + 5 
plt.title("tutorialpro.org - Test", fontproperties=zhfont1) 

# fontproperties to display Chinese, fontsize to set font size
plt.xlabel("x-axis", fontproperties=zhfont1)
plt.ylabel("y-axis", fontproperties=zhfont1)
plt.plot(x,y) 
plt.show()

The output is displayed as follows:

Additionally, we can use system fonts:

from matplotlib import pyplot as plt
import matplotlib
a = sorted([f.name for f in matplotlib.font_manager.fontManager.ttflist])

for i in a:
    print(i)

This prints all registered names from your font_manager's ttflist. Choose a Chinese font, such as STFangsong (Fangsong), and add the following code:

plt.rcParams['font.family'] = ['STFangsong']

We can also customize font styles:

Example

import numpy as np 
from matplotlib import pyplot as plt 
import matplotlib

# fname is the path to the font library you downloaded, note the path to SourceHanSansSC-Bold.otf, size parameter sets font size
zhfont1 = matplotlib.font_manager.FontProperties(fname="SourceHanSansSC-Bold.otf", size=18) 
font1 = {'color':'blue','size':20}
font2 = {'color':'darkred','size':15}
x = np.arange(1,11) 
y = 2 * x + 5 

# fontdict can be used to set font styles with CSS
plt.title("tutorialpro.org - Test", fontproperties=zhfont1, fontdict=font1) 

# fontproperties to display Chinese, fontsize to set font size
plt.xlabel("x-axis", fontproperties=zhfont1)
plt.ylabel("y-axis", fontproperties=zhfont1)
plt.plot(x,y) 
plt.show()

The output is displayed as follows:

Positioning Titles and Labels

The title() method provides a loc parameter to set the title's position, which can be set to: 'left', 'right', and 'center', with 'center' as the default.

The xlabel() method provides a loc parameter to set the x-axis label's position, which can be set to: 'left', 'right', and 'center', with 'center' as the default.

The ylabel() method provides a loc parameter to set the y-axis label's position, which can be set to: 'bottom', 'top', and 'center', with 'center' as the default.

Example

import numpy as np 
from matplotlib import pyplot as plt 
import matplotlib

# fname is the path to the font library you downloaded, note the path to SourceHanSansSC-Bold.otf, size parameter sets font size
zhfont1 = matplotlib.font_manager.FontProperties(fname="SourceHanSansSC-Bold.otf", size=18) 
font1 = {'color':'blue','size':20}
font2 = {'color':'darkred','size':15}
x = np.arange(1,11) 
y = 2 * x + 5 

# fontdict can be used to set font styles with CSS
plt.title("tutorialpro.org - Test", fontproperties=zhfont1, fontdict=font1, loc="left") 

# fontproperties to display Chinese, fontsize to set font size
plt.xlabel("x-axis", fontproperties=zhfont1, loc="left")
plt.ylabel("y-axis", fontproperties=zhfont1, loc="top")
plt.plot(x,y) 
plt.show()

The output is displayed as follows: