如何在下面的情节中添加图例？

Question

Trying to add legend to line plot but not able to do it. Pls suggest some methods or solutions.

counts, bin_edges = np.histogram(df_status_1['nodes'], bins=10, 
density = True)
pdf = counts/(sum(counts))
print(pdf);
print(bin_edges);
cdf = np.cumsum(pdf)
plt.plot(bin_edges[1:],pdf);
plt.plot(bin_edges[1:], cdf)

counts, bin_edges = np.histogram(df_status_2['nodes'], bins=10, 
density = True)
pdf = counts/(sum(counts))
print(pdf);
print(bin_edges);
cdf = np.cumsum(pdf)
plt.xlabel('nodes');
plt.ylabel('values');
plt.title('CDF of long & short surviving ppl');
plt.plot(bin_edges[1:],pdf);
plt.plot(bin_edges[1:], cdf)

Tried to add plt.legend() but getting "No handles with labels found to put in legend" error.enter code here

Answer 1

Store each plt.plot to an axis with coma(plt.plot returns tuple)

ex:

arr1, = plt.plot(bin_edges[1:],pdf);
arr2, = plt.plot(bin_edges[1:], cdf)
plt.legend([arr1,arr2], ['PDF survived','CDF survived']) 

try like above.