在ipython notebook中的matplotlib图中添加任意一行 [英] Adding an arbitrary line to a matplotlib plot in ipython notebook

问题描述

我对python / matplotlib都很陌生，并通过ipython笔记本使用它。我正在尝试向现有图形添加一些注释线，我无法弄清楚如何在图形上渲染线条。因此，例如，如果我绘制以下内容：

I'm rather new to both python/matplotlib and using it through the ipython notebook. I'm trying to add some annotation lines to an existing graph and I can't figure out how to render the lines on a graph. So, for example, if I plot the following:

import numpy as np
np.random.seed(5)
x = arange(1, 101)
y = 20 + 3 * x + np.random.normal(0, 60, 100)
p =  plot(x, y, "o")

我得到以下图表：

那我该如何添加一个垂直线从（70,100）到（70,250）？从（70,100）到（90,200）的对角线怎么样？

So how would I add a vertical line from (70,100) up to (70,250)? What about a diagonal line from (70,100) to (90,200)?

我用 Line2D（）只会导致混淆。在 R 中，我只使用segments（）函数来添加线段。在 matplotlib 中是否存在等价物？

I've tried a few things with Line2D() resulting in nothing but confusion on my part. In R I would simply use the segments() function which would add line segments. Is there an equivalent in matplotlib?

推荐答案

你可以直接绘制通过输入 plot 命令以及相应的数据（段的边界）来获得所需的行：

You can directly plot the lines you want by feeding the plot command with the corresponding data (boundaries of the segments):

plot（[x1，x2]，[y1，y2]，color ='k'，linestyle =' - '，linewidth = 2）

（当然你可以选择颜色，线宽，线条样式等）。

(of course you can choose the color, line width, line style, etc.)

来自你的例子：

import numpy as np
import matplotlib.pyplot as plt

np.random.seed(5)
x = np.arange(1, 101)
y = 20 + 3 * x + np.random.normal(0, 60, 100)
plt.plot(x, y, "o")


# draw vertical line from (70,100) to (70, 250)
plt.plot([70, 70], [100, 250], 'k-', lw=2)

# draw diagonal line from (70, 90) to (90, 200)
plt.plot([70, 90], [90, 200], 'k-')

plt.show()

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