Matplotlib:如何使网格的垂直可选虚线变为虚线? [英] Matplotlib: How to make alternative vertical lines of grid dashed?

问题描述

如果我有简单的整数x轴，则可以使用 plt.axvline(value)来获取垂直线，但我想知道当我们有字符串 x 轴标签时如何获得垂直虚线.

If I had simple integer x-axis, I could use plt.axvline(value) to get vertical lines, but I am wondering how to get vertical dashed lines when we have string x-axis labels.

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt

%matplotlib inline


np.random.seed(123)

x = np.random.normal(0,1,100)
xx = pd.cut(x,20).to_numpy().astype(str)

yy = np.random.normal(0,1,100)

plt.plot(xx,yy,'o')
plt.xticks(rotation=90)
plt.grid(True)

plt.show()

必填

• 网格图中的所有其他垂直线都将变为虚线和彩色.

推荐答案

plt.xticks() 返回 x 个刻度位置和标签，因此我们可以通过使用 [0].事实证明，这只是一个连续整数值的列表，因此我们可以遍历它们并手动绘制网格线，每个网格线使用不同的样式.使用 plt.grid(True, axis='y')，我们确保仅针对 y 轴绘制自动网格，因此这不会干扰我们的自定义垂直线.

plt.xticks() returns the x tick locations and labels, so we can access the locations by indexing with [0]. It turns out this is just a list of consecutive integer values, so we can loop through them and draw the grid lines manually, with a different style for every other one. With plt.grid(True, axis='y') we make sure the automatic grid is drawn only for the y axis, so that this does not interfere with our custom vertical lines.

import numpy as np
import pandas as pd
import matplotlib.pyplot as plt

%matplotlib inline


np.random.seed(123)

x = np.random.normal(0,1,100)
xx = pd.cut(x,20).to_numpy().astype(str)

yy = np.random.normal(0,1,100)

plt.plot(xx,yy,'o')
plt.xticks(rotation=90)

############################
# new code below           #
############################

plt.grid(True, axis='y')

for tick in plt.xticks()[0]:
    if tick % 2 == 0:
        plt.axvline(tick, color='gray', linestyle='-', linewidth=1, alpha=.5)
    else:
        plt.axvline(tick, color='red', linestyle='--', linewidth=1, alpha=1)

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