更改 matplotlib 线型中间图

Question

我正在绘制一些数据（两条线），并且我想更改它们之间差异具有统计显着性的线部分的线型。因此，在下图中（现在链接 b/c 反垃圾邮件政策不允许我发布图像）我希望线条看起来不同（即可能是虚线），直到它们在 35 点左右开始收敛x 轴。

line plot

有没有办法轻松做到这一点？我有 x 轴的值，其中差异很大，我只是不清楚如何更改某些 x 轴位置的线条样式。

Answer 1

编辑：我已经打开并离开了，所以我没有注意到@Ricardo 的回答。因为 matplotlib 无论如何都会将事物转换为 numpy 数组，所以有更有效的方法来做到这一点。

举个例子：

只需绘制两条不同的线，一条为虚线，另一条为实线。

例如

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 10, 100)
y1 = 2 * x
y2 = 3 * x

xthresh = 4.5
diff = np.abs(y1 - y2)
below = diff < xthresh
above = diff >= xthresh

# Plot lines below threshold as dotted...
plt.plot(x[below], y1[below], 'b--')
plt.plot(x[below], y2[below], 'g--')

# Plot lines above threshold as solid...
plt.plot(x[above], y1[above], 'b-')
plt.plot(x[above], y2[above], 'g-')

plt.show()

对于循环的情况，使用掩码数组：

import numpy as np
import matplotlib.pyplot as plt

x = np.linspace(0, 10, 100)
y1 = 2 * np.cos(x)
y2 = 3 * np.sin(x)

xthresh = 2.0
diff = np.abs(y1 - y2)
below = diff < xthresh
above = diff >= xthresh

# Plot lines below threshold as dotted...
plt.plot(np.ma.masked_where(below, x), np.ma.masked_where(below, y1), 'b--')
plt.plot(np.ma.masked_where(below, x), np.ma.masked_where(below, y2), 'g--')

# Plot lines above threshold as solid...
plt.plot(np.ma.masked_where(above, x), np.ma.masked_where(above, y1), 'b-')
plt.plot(np.ma.masked_where(above, x), np.ma.masked_where(above, y2), 'g-')

plt.show()

Answer 2

假设您的数据位于 NumPy 数组 dataset1 和 dataset2 上，并且您已将 threshold 定义为重要意义

def group(data):
    """Assumes that len(data) > 0"""
    prev = 0
    index = 1
    value = data[0]

    while (index < len(data)):
        if data[index] != value:
            yield (value, prev, index)

            value = not value
            prev = index
        index += 1

    yield (value, prev, index)

diff = np.abs(dataset1 - dataset2)
for significant, start, end in group(diff < threshold):
   # Plot data from dataset1[start:end] and dataset2[start:end]
   # Use the value in "significant" (True/False) to figure out
   # The style