Fix random sampling error

Other option would be to use `np.random.choice(range(len(X))`

Author: charlesbmi

examples/shape_learning.py

@@ -57,7 +57,7 @@
 
 
 def random_sampling(classsifier, X):
-    query_idx = np.random.rand(range(len(X)))
+    query_idx = np.random.randint(len(X))
     return query_idx, X[query_idx]
 
 
@@ -100,4 +100,4 @@ def random_sampling(classsifier, X):
     plt.plot(list(range(len(uncertainty_sampling_accuracy))), uncertainty_sampling_accuracy, label="uncertainty sampling")
     plt.plot(list(range(len(random_sampling_accuracy))), random_sampling_accuracy, label="random sampling")
     plt.legend()
-    plt.show()
+    plt.show()