Create customized legend

create_legend.py

import matplotlib.pyplot as plt
from matplotlib.lines import Line2D
import seaborn as sns
import numpy as np
fig = plt.figure()
fig.set_size_inches(18, 3)
ax = fig.subplots(1)
label = ['Expert', 'Demo', 'Pre-train', 'POfD', 'Penalty', 'Penalty + Ann.', 'Ours']
flatui = ["#9b59b6", "#999900", "#3498db", "#95a5a6", "#009900", "#fc9272", "#e74c3c"]
clrs = sns.color_palette(flatui)
custom_lines = [Line2D([0], [0], color=clrs[0], lw=2, linestyle='--'),
                Line2D([0], [0], color=clrs[1], lw=2, linestyle='--'),
                Line2D([0], [0], color=clrs[2], lw=2, linestyle='-'),
                Line2D([0], [0], color=clrs[3], lw=2, linestyle='-'),
                Line2D([0], [0], color=clrs[4], lw=2, linestyle='-'),
                Line2D([0], [0], color=clrs[5], lw=2, linestyle='-'),
                Line2D([0], [0], color=clrs[6], lw=2, linestyle='-')]

with sns.axes_style('darkgrid'):
    for i in range(len(label)):
        ax.plot(np.arange(10), np.ones(10), c=clrs[i])
    box = ax.get_position()
    ax.set_position([box.x0, box.y0 + box.height * 0.1,
                 box.width, box.height * 0.9])
    ax.legend(handles=custom_lines, labels=label, ncol=7, shadow=False, facecolor='white', handlelength=2.0, columnspacing=1.0, handletextpad=0.4, loc='upper center', bbox_to_anchor=(0.5, -0.1))
fig.savefig('legend.pdf')