Python 在matplotlib中使用渐变 colored颜色 填充区域之间

您可以使用fill_between和np.minimum来设置阈值以下的 colored颜色 . 在这条线上用np.maximum来上色.

import numpy as np
import matplotlib.pyplot as plt

y = [54.38,53.99,65.39,66.22,57.65,49.17,42.72,42.07,44.88,46.56,55.27,57.28,60.54,65.87,37.61,44.21,50.62,56.15,52.65,52.17,57.71,61.21,60.77,50.74,62.9,56.51,62.1,52.79,53.96,50.33,48.44,43.72,39.03,36.18,41.6,50.44,50.67,53.68,50.05,47.92,40.43,29.87,24.78,15.53,17.37,20.56,20.3,30.22,38.89,45.04,45.87,47.99,50.97,54.59,53.69,48.09,48.56,47.62,52.78,57.26,48.77,51.6,56.6,58.37,48.39,43.63,42.15,40.05,33.62,48.73,45.29,51.47,50.73,51.52,54.86,49.18,51.03,50.26,45.73,46.7,52.,42.17,49.93,53.08,51.34,52.44,54.06,50.56,51.04,55.47,52.71,52.36,53.59,65.08,62.74,59.23,56.07,49.21,46.67,40.62,44.59,44.89,35.57,37.67,49.74,46.52,38.47,42.08,49.73,53.82,60.76,56.2,56.41,53.83,59.9,51.06,46.9,49.11,36.01,46.72,56.53,59.04,58.52,60.78,60.02,51.78,54.78,52.88,51.73,59.76,67.84,66.63,60.97,53.69,53.17,52.44,46.54,49.08,43.62,40.81,41.64,43.3,46.36,58.07,54.95,50.82,54.17,51.37,55.26,53.55,47.57,36.05,38.66,35.3,51.02,54.96,59.34,53.47,48.34,50.25,54.06,49.99,47.44,41.59,37.58,42.39,41.41,41.84,47.77,52.75,54.84,49.63,51.5,56.26,52.47,49.35,47.13,35.94,28.42,33.14,44.38,56.38,59.63,60.86,64.35,54.59,63.34,74.68,66.29,58.33,57.64,64.64,61.49,59.11,53.72,60.37,56.66,56.92,61.58,57.21,58.12,61.93,45.75,54.77,52.95,50.06,54.54,52.64,48.31,49.9,56.49,54.99,51.83,61.78,50.93,52.92,58.76,58.82,51.26,48.29,41.18,50.69,54.,45.13,48.72,45.32,42.29,30.57,41.28,53.54,55.47,57.54,53.48,50.01,52.42,55.38,53.12,53.31,56.26,57.56,53.87,53.48,53.82,56.8,58.31,60.45,63.22,68.44,76.04,72.14,75.31,64.74,56.5,60.42,54.05,55.62,52.]
x = np.arange(len(y))

ymin = 10
ymax = 80
ythresh = 50

fig, ax = plt.subplots(figsize=(10, 6))
ax.axhline(ythresh, linestyle="--", linewidth=1.0, color="k")
ax.imshow(np.linspace(0, 1, 256).reshape(-1, 1),
          origin='lower', aspect='auto', cmap='Spectral',
          extent=[x[0], x[-1], ymin, ymax])
ax.fill_between(x, ymin, np.minimum(y, ythresh), color="w")
ax.fill_between(x, ymax, np.maximum(y, ythresh), color="w")
ax.plot(x, y, color="k")
plt.show()

这是一个将两个fill_between合并为一个的版本，并使用它来裁剪渐变.这样，原始背景仍然可见.例如，在渐变后面绘制网格线.

此外，值为TwoSlopeNorm会将阈值置于色彩映射表的中心."turbo"色表类似于"Spectral"，但更亮一些.

import matplotlib.pyplot as plt
from matplotlib.colors import TwoSlopeNorm
from matplotlib.patches import PathPatch
import numpy as np

y = [54.38,53.99,65.39,66.22,57.65,49.17,42.72,42.07,44.88,46.56,55.27,57.28,60.54,65.87,37.61,44.21,50.62,56.15,52.65,52.17,57.71,61.21,60.77,50.74,62.9,56.51,62.1,52.79,53.96,50.33,48.44,43.72,39.03,36.18,41.6,50.44,50.67,53.68,50.05,47.92,40.43,29.87,24.78,15.53,17.37,20.56,20.3,30.22,38.89,45.04,45.87,47.99,50.97,54.59,53.69,48.09,48.56,47.62,52.78,57.26,48.77,51.6,56.6,58.37,48.39,43.63,42.15,40.05,33.62,48.73,45.29,51.47,50.73,51.52,54.86,49.18,51.03,50.26,45.73,46.7,52.,42.17,49.93,53.08,51.34,52.44,54.06,50.56,51.04,55.47,52.71,52.36,53.59,65.08,62.74,59.23,56.07,49.21,46.67,40.62,44.59,44.89,35.57,37.67,49.74,46.52,38.47,42.08,49.73,53.82,60.76,56.2,56.41,53.83,59.9,51.06,46.9,49.11,36.01,46.72,56.53,59.04,58.52,60.78,60.02,51.78,54.78,52.88,51.73,59.76,67.84,66.63,60.97,53.69,53.17,52.44,46.54,49.08,43.62,40.81,41.64,43.3,46.36,58.07,54.95,50.82,54.17,51.37,55.26,53.55,47.57,36.05,38.66,35.3,51.02,54.96,59.34,53.47,48.34,50.25,54.06,49.99,47.44,41.59,37.58,42.39,41.41,41.84,47.77,52.75,54.84,49.63,51.5,56.26,52.47,49.35,47.13,35.94,28.42,33.14,44.38,56.38,59.63,60.86,64.35,54.59,63.34,74.68,66.29,58.33,57.64,64.64,61.49,59.11,53.72,60.37,56.66,56.92,61.58,57.21,58.12,61.93,45.75,54.77,52.95,50.06,54.54,52.64,48.31,49.9,56.49,54.99,51.83,61.78,50.93,52.92,58.76,58.82,51.26,48.29,41.18,50.69,54.,45.13,48.72,45.32,42.29,30.57,41.28,53.54,55.47,57.54,53.48,50.01,52.42,55.38,53.12,53.31,56.26,57.56,53.87,53.48,53.82,56.8,58.31,60.45,63.22,68.44,76.04,72.14,75.31,64.74,56.5,60.42,54.05,55.62,52.]
x = np.arange(len(y))

ymin = 10
ymax = 80
ythresh = 50

fig, ax = plt.subplots(figsize=(10, 6))
ax.grid(True, zorder=-1)  # set grid behind the plot
ax.axhline(ythresh, linestyle="--", linewidth=1.0, color="k")

gradient_rect = ax.imshow(np.linspace(ymin, ymax, 256).reshape(-1, 1),
                          origin='lower', aspect='auto', cmap='turbo_r',
                          norm=TwoSlopeNorm(vcenter=ythresh),
                          extent=[x[0], x[-1], ymin, ymax], zorder=1)
fill_poly = ax.fill_between(x, np.minimum(y, 50), np.maximum(y, 50), color="none")
clip_poly = PathPatch(fill_poly.get_paths()[0], transform=ax.transData)
gradient_rect.set_clip_path(clip_poly)
fill_poly.remove() # the polygon isn't needed anymore

ax.plot(x, y, color="k")
plt.show()