plt.legend() 阻止 matplotlib 显示绘图

Question

如果不调用 plt.legend()，则显示绘图。有了它，我得到：

<matplotlib.legend.Legend at 0x1189a404c50>

我在 JupyterLab、Python 3、Anaconda 工作 我不明白是什么阻止了图例的显示。如果没有最后一个 for 循环遍历 xarray，即如果我只加载一个频谱来绘制，则图例工作正常。有任何想法吗？谢谢！ 代码如下：

import colour
from colour.plotting import *
import matplotlib.pyplot as plt
import numpy as np
import pandas as pd
import matplotlib
import scipy.integrate as integrate
from scipy import interpolate

### Read Spectrum file ###
xarray = []
yarray = []
while True:
    # Separator in CSV
    separator = input("Separator: [, or tab or semicolon]")
    if separator in {',','comma'}:
        separator = ','
    elif separator in {'tab','TAB'}:
        separator = '\t'
    elif separator in {';','semicolon'}:
        separator = ';'
    else:
        print("Separator must be one of the listed")

    # Header in CSV
    headerskip = input("Header [y/n]")
    if headerskip in {'y','yes','Y','Yes','YES'}:
        headerskip = 1
    elif headerskip in {'n','no','N','No','NO'}:
        headerskip = 0
    else:
        print("Header?")

    # Choose CSV file
    filename = input("Filename")
    try:
        spectrum = pd.read_csv(filename, sep = separator, header = None, skiprows = headerskip, index_col=0)
    except FileNotFoundError:
        print("Wrong file or file path")

    # Convert to our dictionary
    spec = spectrum[1].to_dict() #functional dictionary
    sample_sd_data = {int(k):v for k,v in spec.items()} # changes index to integer

    # Do color calculations
    sd = colour.SpectralDistribution(sample_sd_data)
    cmfs = colour.STANDARD_OBSERVERS_CMFS['CIE 1931 2 Degree Standard Observer']
    illuminant = colour.ILLUMINANTS_SDS['D65']
    XYZ = colour.sd_to_XYZ(sd, cmfs, illuminant) #tristimulus values.
    print(XYZ)
    xy =  colour.XYZ_to_xy(XYZ) # chromaticity coordinates
    x, y = xy
    print(xy)
    xarray.append(x)
    yarray.append(y)

    # Query to add another file
    addfile = input("Add another spectrum [y,n]")
    if addfile in {'y','yes','Y','Yes','YES'}:
        print("adding another file")

    elif addfile in {'n','no','N','No','NO'}:
        print("done with adding files")
        break
    else:
        print("Add another file? Breaking loop")
        break

# Plotting the *CIE 1931 Chromaticity Diagram*.
# The argument *standalone=False* is passed so that the plot doesn't get
# displayed and can be used as a basis for other plots.
#plot_single_sd(sd)

print(xarray)
print(yarray)

plot_chromaticity_diagram_CIE1931(standalone=False)

# Plotting the *CIE xy* chromaticity coordinates.
for i in range(len(xarray)):
    x = xarray[i]
    y = yarray[i]
    plt.plot(x, y, '-p', color='gray',
        markersize=15, linewidth=4,
        markerfacecolor='None',
        markeredgecolor='gray',
        markeredgewidth=2,
        label=str(i))
plt.plot(.3,.3, '-o', label='test')

# Customizing plot
plt.grid(True, linestyle=':')
plt.axis('equal') # disable this to go x to zero, however it will hide 500nm label
plt.xlim(0,.8)
plt.ylim(0,.9)
#plt.legend(framealpha=1, frameon=True, handlelength=0) # set handlelength to 0 to destroy line over the symbol

Answer 1

您需要在 jupyter 中导入后调用魔术函数 %matplotlib notebook 或 %matplotlib inline。