Repository: alteryx/woodwork (python)

Issue:
Improve Woodwork error message for invalid init calls
If we do
```python
df = pd.Series(["90210", "60018", "10010"] * 100)
df.ww.init()
```
we get the following error:
```python
raise TypeValidationError(
woodwork.exceptions.TypeValidationError: Cannot initialize Woodwork. Series dtype 'object' is incompatible with PostalCode LogicalType. Try converting series dtype to 'category' before initializing or use the woodwork.init_series function to initialize.
```

If we were to follow the first recommendation, we get the following:
```python
df = pd.Series(["90210", "60018", "10010"] * 100).astype('category')
df.ww.init()
df.ww.schema
->
<ColumnSchema (Logical Type = Categorical) (Semantic Tags = ['category'])>
```
The second recommended action is correct, resulting in us getting a postal code logical type.

This issue tracks fixing this message so that users can get accurate inference on their datatables. In the case of series data, we should tell them to use `init_series` rather than `ww.init()`.

Pull request description:
Fix categorical dtype inference for postal code
- closes #1569 

Patch:
diff --git a/docs/source/release_notes.rst b/docs/source/release_notes.rst
index de411e8..04eb051 100644
--- a/docs/source/release_notes.rst
+++ b/docs/source/release_notes.rst
@@ -14,6 +14,7 @@ Future Release
         * Fixed ``IntegerNullable`` inference by checking values are within valid ``Int64`` bounds (:pr:`1572`)
         * Update demo dataset links to point to new endpoint (:pr:`1570`)
         * Fix DivisionByZero error in ``type_system.py`` (:pr:`1571`)
+        * Fix Categorical dtype inference for ``PostalCode`` logical type (:pr:`1574`)
         * Fixed issue where forcing a ``Boolean`` logical type on a column of 0.0s and 1.0s caused incorrect transformation (:pr:`1576`)
     * Changes
         * Unpin dask dependency (:pr:`1561`)
diff --git a/woodwork/type_sys/inference_functions.py b/woodwork/type_sys/inference_functions.py
index f6d1699..af543be 100644
--- a/woodwork/type_sys/inference_functions.py
+++ b/woodwork/type_sys/inference_functions.py
@@ -156,7 +156,10 @@ class InferWithRegex:
         regex = self.get_regex()
 
         # Includes a check for object dtypes
-        if not pdtypes.is_string_dtype(series.dtype):
+        if not (
+            pdtypes.is_categorical_dtype(series.dtype)
+            or pdtypes.is_string_dtype(series.dtype)
+        ):
             return False
 
         try:


Test patch:
diff --git a/woodwork/tests/type_system/conftest.py b/woodwork/tests/type_system/conftest.py
index 2b48563..2059aad 100644
--- a/woodwork/tests/type_system/conftest.py
+++ b/woodwork/tests/type_system/conftest.py
@@ -282,6 +282,33 @@ def natural_language(request):
     return request.getfixturevalue(request.param)
 
 
+# Postal Inference Fixtures
+@pytest.fixture
+def pandas_postal_codes():
+    return [
+        pd.Series(10 * ["77002", "55106"]),
+        pd.Series(10 * ["77002-0000", "55106-0000"]),
+        pd.Series(10 * ["12345", "12345", "12345-6789", "12345-0000"]),
+    ]
+
+
+@pytest.fixture
+def dask_postal_codes(pandas_postal_codes):
+    return [pd_to_dask(series) for series in pandas_postal_codes]
+
+
+@pytest.fixture
+def spark_postal_codes(pandas_postal_codes):
+    return [pd_to_spark(series) for series in pandas_postal_codes]
+
+
+@pytest.fixture(
+    params=["pandas_postal_codes", "dask_postal_codes", "spark_postal_codes"],
+)
+def postal(request):
+    return request.getfixturevalue(request.param)
+
+
 # Unknown Inference Fixtures
 @pytest.fixture
 def pandas_strings():
@@ -357,7 +384,7 @@ def pyspark_empty_series(pandas_empty_series):
 
 
 @pytest.fixture(
-    params=["pandas_empty_series", "dask_empty_series", "pyspark_empty_series"]
+    params=["pandas_empty_series", "dask_empty_series", "pyspark_empty_series"],
 )
 def empty_series(request):
     return request.getfixturevalue(request.param)
diff --git a/woodwork/tests/type_system/test_ltype_inference.py b/woodwork/tests/type_system/test_ltype_inference.py
index 9a3d41a..b5c7b46 100644
--- a/woodwork/tests/type_system/test_ltype_inference.py
+++ b/woodwork/tests/type_system/test_ltype_inference.py
@@ -13,6 +13,7 @@ from woodwork.logical_types import (
     IntegerNullable,
     LogicalType,
     NaturalLanguage,
+    PostalCode,
     Timedelta,
     Unknown,
 )
@@ -132,6 +133,16 @@ def test_categorical_inference(categories):
             assert isinstance(inferred_type, Categorical)
 
 
+def test_postal_inference(postal):
+    dtypes = ["category", "string"]
+    for series in postal:
+        if _is_spark_series(series):
+            dtypes = get_spark_dtypes(dtypes)
+        for dtype in dtypes:
+            inferred_dtype = ww.type_system.infer_logical_type(series.astype(dtype))
+            assert isinstance(inferred_dtype, PostalCode)
+
+
 def test_natural_language_inference(natural_language):
     dtypes = ["object", "string"]
     if _is_spark_series(natural_language[0]):