diff --git a/miplearn/components/dynamic_common.py b/miplearn/components/dynamic_common.py
index 0b48f6f..dbfd5e7 100644
--- a/miplearn/components/dynamic_common.py
+++ b/miplearn/components/dynamic_common.py
@@ -56,6 +56,11 @@ class DynamicConstraintsComponent(Component):
         cids: Dict[ConstraintCategory, List[ConstraintName]] = {}
         known_cids = np.array(self.known_cids, dtype="S")
 
+        enforced_cids = None
+        enforced_cids_np = sample.get_array(self.attr)
+        if enforced_cids_np is not None:
+            enforced_cids = list(enforced_cids_np)
+
         # Get user-provided constraint features
         (
             constr_features,
@@ -72,13 +77,11 @@ class DynamicConstraintsComponent(Component):
                 constr_features,
             ]
         )
-        assert len(known_cids) == constr_features.shape[0]
 
         categories = np.unique(constr_categories)
         for c in categories:
             x[c] = constr_features[constr_categories == c].tolist()
             cids[c] = known_cids[constr_categories == c].tolist()
-            enforced_cids = np.array(list(sample.get_set(self.attr)), dtype="S")
             if enforced_cids is not None:
                 tmp = np.isin(cids[c], enforced_cids).reshape(-1, 1)
                 y[c] = np.hstack([~tmp, tmp]).tolist()  # type: ignore
@@ -99,7 +102,7 @@ class DynamicConstraintsComponent(Component):
         assert pre is not None
         known_cids: Set = set()
         for cids in pre:
-            known_cids |= cids
+            known_cids |= set(list(cids))
         self.known_cids.clear()
         self.known_cids.extend(sorted(known_cids))
 
@@ -128,7 +131,7 @@ class DynamicConstraintsComponent(Component):
 
     @overrides
     def pre_sample_xy(self, instance: Instance, sample: Sample) -> Any:
-        return sample.get_set(self.attr)
+        return sample.get_array(self.attr)
 
     @overrides
     def fit_xy(
@@ -150,7 +153,7 @@ class DynamicConstraintsComponent(Component):
         instance: Instance,
         sample: Sample,
     ) -> Dict[str, float]:
-        actual = sample.get_set(self.attr)
+        actual = sample.get_array(self.attr)
         assert actual is not None
         pred = set(self.sample_predict(instance, sample))
         tp, tn, fp, fn = 0, 0, 0, 0
diff --git a/miplearn/components/dynamic_lazy.py b/miplearn/components/dynamic_lazy.py
index 9e82556..7756e64 100644
--- a/miplearn/components/dynamic_lazy.py
+++ b/miplearn/components/dynamic_lazy.py
@@ -3,6 +3,7 @@
 #  Released under the modified BSD license. See COPYING.md for more details.
 
 import logging
+import pdb
 from typing import Dict, List, TYPE_CHECKING, Tuple, Any, Optional, Set
 
 import numpy as np
@@ -78,7 +79,10 @@ class DynamicLazyConstraintsComponent(Component):
         stats: LearningSolveStats,
         sample: Sample,
     ) -> None:
-        sample.put_set("mip_constr_lazy_enforced", set(self.lazy_enforced))
+        sample.put_array(
+            "mip_constr_lazy_enforced",
+            np.array(list(self.lazy_enforced), dtype="S"),
+        )
 
     @overrides
     def iteration_cb(
diff --git a/miplearn/components/dynamic_user_cuts.py b/miplearn/components/dynamic_user_cuts.py
index 3fe3298..b48d7e7 100644
--- a/miplearn/components/dynamic_user_cuts.py
+++ b/miplearn/components/dynamic_user_cuts.py
@@ -87,7 +87,10 @@ class UserCutsComponent(Component):
         stats: LearningSolveStats,
         sample: Sample,
     ) -> None:
-        sample.put_set("mip_user_cuts_enforced", set(self.enforced))
+        sample.put_array(
+            "mip_user_cuts_enforced",
+            np.array(list(self.enforced), dtype="S"),
+        )
         stats["UserCuts: Added in callback"] = self.n_added_in_callback
         if self.n_added_in_callback > 0:
             logger.info(f"{self.n_added_in_callback} user cuts added in callback")
diff --git a/miplearn/components/static_lazy.py b/miplearn/components/static_lazy.py
index 2dd300e..e819755 100644
--- a/miplearn/components/static_lazy.py
+++ b/miplearn/components/static_lazy.py
@@ -61,7 +61,10 @@ class StaticLazyConstraintsComponent(Component):
         stats: LearningSolveStats,
         sample: Sample,
     ) -> None:
-        sample.put_set("mip_constr_lazy_enforced", self.enforced_cids)
+        sample.put_array(
+            "mip_constr_lazy_enforced",
+            np.array(list(self.enforced_cids), dtype="S"),
+        )
         stats["LazyStatic: Restored"] = self.n_restored
         stats["LazyStatic: Iterations"] = self.n_iterations
 
@@ -212,7 +215,7 @@ class StaticLazyConstraintsComponent(Component):
         constr_names = sample.get_array("static_constr_names")
         constr_categories = sample.get_array("static_constr_categories")
         constr_lazy = sample.get_array("static_constr_lazy")
-        lazy_enforced = sample.get_set("mip_constr_lazy_enforced")
+        lazy_enforced = sample.get_array("mip_constr_lazy_enforced")
         if constr_features is None:
             constr_features = sample.get_array("static_constr_features")
 
diff --git a/miplearn/features/sample.py b/miplearn/features/sample.py
index 6afde9e..df50552 100644
--- a/miplearn/features/sample.py
+++ b/miplearn/features/sample.py
@@ -46,15 +46,6 @@ class Sample(ABC):
     def put_scalar(self, key: str, value: Scalar) -> None:
         pass
 
-    @abstractmethod
-    def get_vector(self, key: str) -> Optional[Any]:
-        warnings.warn("Deprecated", DeprecationWarning)
-        return None
-
-    @abstractmethod
-    def put_vector(self, key: str, value: Vector) -> None:
-        warnings.warn("Deprecated", DeprecationWarning)
-
     @abstractmethod
     def put_array(self, key: str, value: Optional[np.ndarray]) -> None:
         pass
@@ -71,19 +62,6 @@ class Sample(ABC):
     def get_sparse(self, key: str) -> Optional[coo_matrix]:
         pass
 
-    def get_set(self, key: str) -> Set:
-        warnings.warn("Deprecated", DeprecationWarning)
-        v = self.get_vector(key)
-        if v:
-            return set(v)
-        else:
-            return set()
-
-    def put_set(self, key: str, value: Set) -> None:
-        warnings.warn("Deprecated", DeprecationWarning)
-        v = list(value)
-        self.put_vector(key, v)
-
     def _assert_is_scalar(self, value: Any) -> None:
         if value is None:
             return
@@ -91,20 +69,13 @@ class Sample(ABC):
             return
         assert False, f"scalar expected; found instead: {value} ({value.__class__})"
 
-    def _assert_is_vector(self, value: Any) -> None:
-        assert isinstance(
-            value, (list, np.ndarray)
-        ), f"list or numpy array expected; found instead: {value} ({value.__class__})"
-        for v in value:
-            self._assert_is_scalar(v)
-
-    def _assert_supported(self, value: np.ndarray) -> None:
+    def _assert_is_array(self, value: np.ndarray) -> None:
         assert isinstance(value, np.ndarray)
         assert value.dtype.kind in "biufS", f"Unsupported dtype: {value.dtype}"
 
     def _assert_is_sparse(self, value: Any) -> None:
         assert isinstance(value, coo_matrix)
-        self._assert_supported(value.data)
+        self._assert_is_array(value.data)
 
 
 class MemorySample(Sample):
@@ -113,35 +84,20 @@ class MemorySample(Sample):
     def __init__(
         self,
         data: Optional[Dict[str, Any]] = None,
-        check_data: bool = True,
     ) -> None:
         if data is None:
             data = {}
         self._data: Dict[str, Any] = data
-        self._check_data = check_data
 
     @overrides
     def get_scalar(self, key: str) -> Optional[Any]:
         return self._get(key)
 
-    @overrides
-    def get_vector(self, key: str) -> Optional[Any]:
-        return self._get(key)
-
     @overrides
     def put_scalar(self, key: str, value: Scalar) -> None:
         if value is None:
             return
-        if self._check_data:
-            self._assert_is_scalar(value)
-        self._put(key, value)
-
-    @overrides
-    def put_vector(self, key: str, value: Vector) -> None:
-        if value is None:
-            return
-        if self._check_data:
-            self._assert_is_vector(value)
+        self._assert_is_scalar(value)
         self._put(key, value)
 
     def _get(self, key: str) -> Optional[Any]:
@@ -157,7 +113,7 @@ class MemorySample(Sample):
     def put_array(self, key: str, value: Optional[np.ndarray]) -> None:
         if value is None:
             return
-        self._assert_supported(value)
+        self._assert_is_array(value)
         self._put(key, value)
 
     @overrides
@@ -188,10 +144,8 @@ class Hdf5Sample(Sample):
         self,
         filename: str,
         mode: str = "r+",
-        check_data: bool = True,
     ) -> None:
         self.file = h5py.File(filename, mode, libver="latest")
-        self._check_data = check_data
 
     @overrides
     def get_scalar(self, key: str) -> Optional[Any]:
@@ -206,66 +160,20 @@ class Hdf5Sample(Sample):
         else:
             return ds[()].tolist()
 
-    @overrides
-    def get_vector(self, key: str) -> Optional[Any]:
-        if key not in self.file:
-            return None
-        ds = self.file[key]
-        assert (
-            len(ds.shape) == 1
-        ), f"1-dimensional array expected; found shape {ds.shape}"
-        if h5py.check_string_dtype(ds.dtype):
-            result = ds.asstr()[:].tolist()
-            result = [r if len(r) > 0 else None for r in result]
-            return result
-        else:
-            return ds[:].tolist()
-
     @overrides
     def put_scalar(self, key: str, value: Any) -> None:
         if value is None:
             return
-        if self._check_data:
-            self._assert_is_scalar(value)
-        self._put(key, value)
-
-    @overrides
-    def put_vector(self, key: str, value: Vector) -> None:
-        if value is None:
-            return
-        if self._check_data:
-            self._assert_is_vector(value)
-
-        for v in value:
-            # Convert strings to bytes
-            if isinstance(v, str) or v is None:
-                value = np.array(
-                    [u if u is not None else b"" for u in value],
-                    dtype="S",
-                )
-                break
-
-            # Convert all floating point numbers to half-precision
-            if isinstance(v, float):
-                value = np.array(value, dtype=np.dtype("f2"))
-                break
-
-        self._put(key, value, compress=True)
-
-    def _put(self, key: str, value: Any, compress: bool = False) -> Dataset:
+        self._assert_is_scalar(value)
         if key in self.file:
             del self.file[key]
-        if compress:
-            ds = self.file.create_dataset(key, data=value, compression="gzip")
-        else:
-            ds = self.file.create_dataset(key, data=value)
-        return ds
+        self.file.create_dataset(key, data=value)
 
     @overrides
     def put_array(self, key: str, value: Optional[np.ndarray]) -> None:
         if value is None:
             return
-        self._assert_supported(value)
+        self._assert_is_array(value)
         if key in self.file:
             del self.file[key]
         return self.file.create_dataset(key, data=value, compression="gzip")
diff --git a/tests/components/test_dynamic_lazy.py b/tests/components/test_dynamic_lazy.py
index e46c116..4fbdc0b 100644
--- a/tests/components/test_dynamic_lazy.py
+++ b/tests/components/test_dynamic_lazy.py
@@ -24,13 +24,13 @@ def training_instances() -> List[Instance]:
     samples_0 = [
         MemorySample(
             {
-                "mip_constr_lazy_enforced": {b"c1", b"c2"},
+                "mip_constr_lazy_enforced": np.array(["c1", "c2"], dtype="S"),
                 "static_instance_features": np.array([5.0]),
             },
         ),
         MemorySample(
             {
-                "mip_constr_lazy_enforced": {b"c2", b"c3"},
+                "mip_constr_lazy_enforced": np.array(["c2", "c3"], dtype="S"),
                 "static_instance_features": np.array([5.0]),
             },
         ),
@@ -55,7 +55,7 @@ def training_instances() -> List[Instance]:
     samples_1 = [
         MemorySample(
             {
-                "mip_constr_lazy_enforced": {b"c3", b"c4"},
+                "mip_constr_lazy_enforced": np.array(["c3", "c4"], dtype="S"),
                 "static_instance_features": np.array([8.0]),
             },
         )
@@ -81,7 +81,12 @@ def training_instances() -> List[Instance]:
 
 def test_sample_xy(training_instances: List[Instance]) -> None:
     comp = DynamicLazyConstraintsComponent()
-    comp.pre_fit([{b"c1", b"c2", b"c3", b"c4"}])
+    comp.pre_fit(
+        [
+            np.array(["c1", "c3", "c4"], dtype="S"),
+            np.array(["c1", "c2", "c4"], dtype="S"),
+        ]
+    )
     x_expected = {
         b"type-a": np.array([[5.0, 1.0, 2.0, 3.0], [5.0, 4.0, 5.0, 6.0]]),
         b"type-b": np.array([[5.0, 1.0, 2.0, 0.0], [5.0, 3.0, 4.0, 0.0]]),
diff --git a/tests/components/test_dynamic_user_cuts.py b/tests/components/test_dynamic_user_cuts.py
index ab8e25c..2bae1a6 100644
--- a/tests/components/test_dynamic_user_cuts.py
+++ b/tests/components/test_dynamic_user_cuts.py
@@ -82,7 +82,7 @@ def test_usage(
 ) -> None:
     stats_before = solver.solve(stab_instance)
     sample = stab_instance.get_samples()[0]
-    user_cuts_enforced = sample.get_set("mip_user_cuts_enforced")
+    user_cuts_enforced = sample.get_array("mip_user_cuts_enforced")
     assert user_cuts_enforced is not None
     assert len(user_cuts_enforced) > 0
     assert stats_before["UserCuts: Added ahead-of-time"] == 0
diff --git a/tests/components/test_static_lazy.py b/tests/components/test_static_lazy.py
index 5a38822..9455dcd 100644
--- a/tests/components/test_static_lazy.py
+++ b/tests/components/test_static_lazy.py
@@ -19,6 +19,7 @@ from miplearn.types import (
     LearningSolveStats,
     ConstraintCategory,
 )
+from miplearn.solvers.tests import assert_equals
 
 
 @pytest.fixture
@@ -35,7 +36,7 @@ def sample() -> Sample:
             "static_constr_lazy": np.array([True, True, True, True, False]),
             "static_constr_names": np.array(["c1", "c2", "c3", "c4", "c5"], dtype="S"),
             "static_instance_features": [5.0],
-            "mip_constr_lazy_enforced": {b"c1", b"c2", b"c4"},
+            "mip_constr_lazy_enforced": np.array(["c1", "c2", "c4"], dtype="S"),
             "lp_constr_features": np.array(
                 [
                     [1.0, 1.0, 0.0],
@@ -96,7 +97,7 @@ def test_usage_with_solver(instance: Instance) -> None:
 
     stats: LearningSolveStats = {}
     sample = instance.get_samples()[0]
-    assert sample.get_set("mip_constr_lazy_enforced") is not None
+    assert sample.get_array("mip_constr_lazy_enforced") is not None
 
     # LearningSolver calls before_solve_mip
     component.before_solve_mip(
@@ -145,8 +146,13 @@ def test_usage_with_solver(instance: Instance) -> None:
     )
 
     # Should update training sample
-    assert sample.get_set("mip_constr_lazy_enforced") == {b"c1", b"c2", b"c3", b"c4"}
-    #
+    mip_constr_lazy_enforced = sample.get_array("mip_constr_lazy_enforced")
+    assert mip_constr_lazy_enforced is not None
+    assert_equals(
+        sorted(mip_constr_lazy_enforced),
+        np.array(["c1", "c2", "c3", "c4"], dtype="S"),
+    )
+
     # Should update stats
     assert stats["LazyStatic: Removed"] == 1
     assert stats["LazyStatic: Kept"] == 3
diff --git a/tests/features/test_extractor.py b/tests/features/test_extractor.py
index c6527f7..056a1bb 100644
--- a/tests/features/test_extractor.py
+++ b/tests/features/test_extractor.py
@@ -77,7 +77,7 @@ def test_knapsack() -> None:
         np.array(["eq_capacity"], dtype="S"),
     )
     # assert_equals(
-    #     sample.get_vector("static_constr_lhs"),
+    #     sample.get_array("static_constr_lhs"),
     #     [
     #         [
     #             ("x[0]", 23.0),
@@ -89,7 +89,7 @@ def test_knapsack() -> None:
     #     ],
     # )
     assert_equals(
-        sample.get_vector("static_constr_rhs"),
+        sample.get_array("static_constr_rhs"),
         np.array([0.0]),
     )
     assert_equals(
@@ -97,11 +97,11 @@ def test_knapsack() -> None:
         np.array(["="], dtype="S"),
     )
     assert_equals(
-        sample.get_vector("static_constr_features"),
+        sample.get_array("static_constr_features"),
         np.array([[0.0]]),
     )
     assert_equals(
-        sample.get_vector("static_constr_categories"),
+        sample.get_array("static_constr_categories"),
         np.array(["eq_capacity"], dtype="S"),
     )
     assert_equals(
@@ -109,7 +109,7 @@ def test_knapsack() -> None:
         np.array([False]),
     )
     assert_equals(
-        sample.get_vector("static_instance_features"),
+        sample.get_array("static_instance_features"),
         np.array([67.0, 21.75]),
     )
     assert_equals(sample.get_scalar("static_constr_lazy_count"), 0)
diff --git a/tests/instance/test_file.py b/tests/instance/test_file.py
index 4beb80a..bad2fc5 100644
--- a/tests/instance/test_file.py
+++ b/tests/instance/test_file.py
@@ -17,7 +17,7 @@ def test_usage() -> None:
     # Save instance to disk
     filename = tempfile.mktemp()
     FileInstance.save(original, filename)
-    sample = Hdf5Sample(filename, check_data=True)
+    sample = Hdf5Sample(filename)
     assert len(sample.get_array("pickled")) > 0
 
     # Solve instance from disk
diff --git a/tests/problems/test_tsp.py b/tests/problems/test_tsp.py
index 99a4be6..8572635 100644
--- a/tests/problems/test_tsp.py
+++ b/tests/problems/test_tsp.py
@@ -66,7 +66,7 @@ def test_subtour() -> None:
     samples = instance.get_samples()
     assert len(samples) == 1
     sample = samples[0]
-    lazy_enforced = sample.get_set("mip_constr_lazy_enforced")
+    lazy_enforced = sample.get_array("mip_constr_lazy_enforced")
     assert lazy_enforced is not None
     assert len(lazy_enforced) > 0
     assert_equals(