擅长:python、mysql、java
<p>只需设置图例句柄的<code>linewidth</code>:</p>
<pre><code>In [55]: fig, ax = plt.subplots()
In [56]: x = np.arange(10)
In [57]: for i in xrange(5):
....: ax.plot(x, i * x, label='$y = %ix$' % i)
....:
In [58]: leg = ax.legend(loc='best')
In [59]: for l in leg.legendHandles:
....: l.set_linewidth(10)
....:
</code></pre>
<p><img src="https://i.stack.imgur.com/FDwcn.png" alt="legend_linewidth.png"/></p>