使用连续的颜色谱

import matplotlib.pyplot as plt
import matplotlib.colors as colors
import matplotlib.cm as cmx
import numpy as np

# define some random data that emulates your indeded code:
NCURVES = 100
values = range(NCURVES)
datas = [XRs[i][0].T- x[0].T for i in range(NCURVES)]  # 需要绘制的曲线

fig = plt.figure()
ax = fig.add_subplot(111)
cm = plt.get_cmap('nipy_spectral') 
cNorm  = colors.Normalize(vmin=0, vmax=values[-1])  # 设置离散 value 的取值范围
scalarMap = cmx.ScalarMappable(norm=cNorm, cmap=cm)

lines = []
for idx in range(NCURVES):
    colorVal = scalarMap.to_rgba(values[idx]) # 根据 value 提取颜色
    colorText = (
        'color: (%4.2f,%4.2f,%4.2f)'%(colorVal[0],colorVal[1],colorVal[2])
        )

    retLine = ax.plot(datas[idx],
                       color=colorVal,
                       label=colorText)
    lines.append(retLine)
#added this to get the legend to work
handles,labels = ax.get_legend_handles_labels()
ax.legend(handles, labels, loc='upper right')
ax.grid()
plt.show()