REF: de-duplicate _format_attrs (pandas-dev#41655)

Author: jbrockmendel

pandas/core/indexes/base.py

@@ -1158,14 +1158,18 @@ def _format_data(self, name=None) -> str_t:
                 is_justify = False
 
         return format_object_summary(
-            self, self._formatter_func, is_justify=is_justify, name=name
+            self,
+            self._formatter_func,
+            is_justify=is_justify,
+            name=name,
+            line_break_each_value=self._is_multi,
         )
 
-    def _format_attrs(self):
+    def _format_attrs(self) -> list[tuple[str_t, str_t | int]]:
         """
         Return a list of tuples of the (attr,formatted_value).
         """
-        return format_object_attrs(self)
+        return format_object_attrs(self, include_dtype=not self._is_multi)
 
     def _mpl_repr(self):
         # how to represent ourselves to matplotlib
@@ -2407,6 +2411,13 @@ def is_all_dates(self) -> bool:
         )
         return self._is_all_dates
 
+    @cache_readonly
+    def _is_multi(self) -> bool:
+        """
+        Cached check equivalent to isinstance(self, MultiIndex)
+        """
+        return isinstance(self, ABCMultiIndex)
+
     # --------------------------------------------------------------------
     # Pickle Methods
 

pandas/core/indexes/category.py

@@ -335,13 +335,8 @@ def _format_attrs(self):
             # error: "CategoricalIndex" has no attribute "ordered"
             ("ordered", self.ordered),  # type: ignore[attr-defined]
         ]
-        if self.name is not None:
-            attrs.append(("name", ibase.default_pprint(self.name)))
-        attrs.append(("dtype", f"'{self.dtype.name}'"))
-        max_seq_items = get_option("display.max_seq_items") or len(self)
-        if len(self) > max_seq_items:
-            attrs.append(("length", len(self)))
-        return attrs
+        extra = super()._format_attrs()
+        return attrs + extra
 
     def _format_with_header(self, header: list[str], na_rep: str = "NaN") -> list[str]:
         from pandas.io.formats.printing import pprint_thing

pandas/core/indexes/datetimelike.py

@@ -361,7 +361,9 @@ def _format_attrs(self):
                 freq = self.freqstr
                 if freq is not None:
                     freq = repr(freq)
-                attrs.append(("freq", freq))
+                # Argument 1 to "append" of "list" has incompatible type
+                # "Tuple[str, Optional[str]]"; expected "Tuple[str, Union[str, int]]"
+                attrs.append(("freq", freq))  # type: ignore[arg-type]
         return attrs
 
     def _summary(self, name=None) -> str:

pandas/core/indexes/interval.py

@@ -16,8 +16,6 @@
 
 import numpy as np
 
-from pandas._config import get_option
-
 from pandas._libs import lib
 from pandas._libs.interval import (
     Interval,
@@ -80,7 +78,6 @@
 from pandas.core.indexes.base import (
     Index,
     _index_shared_docs,
-    default_pprint,
     ensure_index,
     maybe_extract_name,
 )
@@ -919,49 +916,9 @@ def _format_native_types(self, na_rep="NaN", quoting=None, **kwargs):
         return super()._format_native_types(na_rep=na_rep, quoting=quoting, **kwargs)
 
     def _format_data(self, name=None) -> str:
-
         # TODO: integrate with categorical and make generic
         # name argument is unused here; just for compat with base / categorical
-        n = len(self)
-        max_seq_items = min((get_option("display.max_seq_items") or n) // 10, 10)
-
-        formatter = str
-
-        if n == 0:
-            summary = "[]"
-        elif n == 1:
-            first = formatter(self[0])
-            summary = f"[{first}]"
-        elif n == 2:
-            first = formatter(self[0])
-            last = formatter(self[-1])
-            summary = f"[{first}, {last}]"
-        else:
-
-            if n > max_seq_items:
-                n = min(max_seq_items // 2, 10)
-                head = [formatter(x) for x in self[:n]]
-                tail = [formatter(x) for x in self[-n:]]
-                head_joined = ", ".join(head)
-                tail_joined = ", ".join(tail)
-                summary = f"[{head_joined} ... {tail_joined}]"
-            else:
-                tail = [formatter(x) for x in self]
-                joined = ", ".join(tail)
-                summary = f"[{joined}]"
-
-        return summary + "," + self._format_space()
-
-    def _format_attrs(self):
-        attrs = []
-        if self.name is not None:
-            attrs.append(("name", default_pprint(self.name)))
-        attrs.append(("dtype", f"'{self.dtype}'"))
-        return attrs
-
-    def _format_space(self) -> str:
-        space = " " * (len(type(self).__name__) + 1)
-        return f"\n{space}"
+        return self._data._format_data() + "," + self._format_space()
 
     # --------------------------------------------------------------------
     # Set Operations

pandas/core/indexes/multi.py

@@ -89,11 +89,7 @@
     lexsort_indexer,
 )
 
-from pandas.io.formats.printing import (
-    format_object_attrs,
-    format_object_summary,
-    pprint_thing,
-)
+from pandas.io.formats.printing import pprint_thing
 
 if TYPE_CHECKING:
     from pandas import (
@@ -1287,20 +1283,6 @@ def _formatter_func(self, tup):
         formatter_funcs = [level._formatter_func for level in self.levels]
         return tuple(func(val) for func, val in zip(formatter_funcs, tup))
 
-    def _format_data(self, name=None) -> str:
-        """
-        Return the formatted data as a unicode string
-        """
-        return format_object_summary(
-            self, self._formatter_func, name=name, line_break_each_value=True
-        )
-
-    def _format_attrs(self):
-        """
-        Return a list of tuples of the (attr,formatted_value).
-        """
-        return format_object_attrs(self, include_dtype=False)
-
     def _format_native_types(self, na_rep="nan", **kwargs):
         new_levels = []
         new_codes = []