Add is_boolean, is_categorical, is_floating, is_integer, is_interval, is_numeric and is_object in Index and MultiIndex (#795)

See https://pandas.pydata.org/pandas-docs/stable/reference/indexing.html

Author: HyukjinKwon

databricks/koalas/indexes.py

@@ -22,7 +22,9 @@
 from typing import Any, List, Optional, Tuple, Union
 
 import pandas as pd
-from pandas.api.types import is_list_like
+from pandas.api.types import is_list_like, is_interval_dtype, is_bool_dtype, \
+    is_categorical_dtype, is_integer_dtype, is_float_dtype, is_numeric_dtype, is_object_dtype
+
 from pyspark import sql as spark
 from pyspark.sql import functions as F
 
@@ -239,6 +241,83 @@ def to_series(self, name: Union[str, Tuple[str, ...]] = None) -> Series:
                                          column_index_names=None),
                       anchor=kdf)
 
+    def is_boolean(self):
+        """
+        Return if the current index type is a boolean type.
+
+        Examples
+        --------
+        >>> ks.DataFrame({'a': [1]}, index=[True]).index.is_boolean()
+        True
+        """
+        return is_bool_dtype(self.dtype)
+
+    def is_categorical(self):
+        """
+        Return if the current index type is a categorical type.
+
+        Examples
+        --------
+        >>> ks.DataFrame({'a': [1]}, index=[1]).index.is_categorical()
+        False
+        """
+        return is_categorical_dtype(self.dtype)
+
+    def is_floating(self):
+        """
+        Return if the current index type is a floating type.
+
+        Examples
+        --------
+        >>> ks.DataFrame({'a': [1]}, index=[1]).index.is_floating()
+        False
+        """
+        return is_float_dtype(self.dtype)
+
+    def is_integer(self):
+        """
+        Return if the current index type is a integer type.
+
+        Examples
+        --------
+        >>> ks.DataFrame({'a': [1]}, index=[1]).index.is_integer()
+        True
+        """
+        return is_integer_dtype(self.dtype)
+
+    def is_interval(self):
+        """
+        Return if the current index type is an interval type.
+
+        Examples
+        --------
+        >>> ks.DataFrame({'a': [1]}, index=[1]).index.is_interval()
+        False
+        """
+        return is_interval_dtype(self.dtype)
+
+    def is_numeric(self):
+        """
+        Return if the current index type is a numeric type.
+
+        Examples
+        --------
+        >>> ks.DataFrame({'a': [1]}, index=[1]).index.is_numeric()
+        True
+        """
+        return is_numeric_dtype(self.dtype)
+
+    def is_object(self):
+        """
+        Return if the current index type is a object type.
+
+        Examples
+        --------
+        >>> ks.DataFrame({'a': [1]}, index=["a"]).index.is_object()
+        True
+        """
+        return is_object_dtype(self.dtype)
+
     def __getattr__(self, item: str) -> Any:
         if hasattr(_MissingPandasLikeIndex, item):
             property_or_func = getattr(_MissingPandasLikeIndex, item)

databricks/koalas/missing/indexes.py

@@ -76,15 +76,8 @@ class _MissingPandasLikeIndex(object):
     insert = unsupported_function('insert')
     intersection = unsupported_function('intersection')
     is_ = unsupported_function('is_')
-    is_boolean = unsupported_function('is_boolean')
-    is_categorical = unsupported_function('is_categorical')
-    is_floating = unsupported_function('is_floating')
-    is_integer = unsupported_function('is_integer')
-    is_interval = unsupported_function('is_interval')
     is_lexsorted_for_tuple = unsupported_function('is_lexsorted_for_tuple')
     is_mixed = unsupported_function('is_mixed')
-    is_numeric = unsupported_function('is_numeric')
-    is_object = unsupported_function('is_object')
     is_type_compatible = unsupported_function('is_type_compatible')
     join = unsupported_function('join')
     map = unsupported_function('map')
@@ -189,16 +182,9 @@ class _MissingPandasLikeMultiIndex(object):
     insert = unsupported_function('insert')
     intersection = unsupported_function('intersection')
     is_ = unsupported_function('is_')
-    is_boolean = unsupported_function('is_boolean')
-    is_categorical = unsupported_function('is_categorical')
-    is_floating = unsupported_function('is_floating')
-    is_integer = unsupported_function('is_integer')
-    is_interval = unsupported_function('is_interval')
     is_lexsorted = unsupported_function('is_lexsorted')
     is_lexsorted_for_tuple = unsupported_function('is_lexsorted_for_tuple')
     is_mixed = unsupported_function('is_mixed')
-    is_numeric = unsupported_function('is_numeric')
-    is_object = unsupported_function('is_object')
     is_type_compatible = unsupported_function('is_type_compatible')
     join = unsupported_function('join')
     map = unsupported_function('map')

docs/source/reference/indexing.rst

@@ -23,6 +23,20 @@ Properties
    Index.names
    Index.empty
 
+Modifying and computations
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+.. autosummary::
+   :toctree: api/
+
+   Index.is_boolean
+   Index.is_categorical
+   Index.is_floating
+   Index.is_integer
+   Index.is_interval
+   Index.is_numeric
+   Index.is_object
+
 Missing Values
 ~~~~~~~~~~~~~~
 .. autosummary::