Address PR comments

pandas/core/frame.py

@@ -1909,22 +1909,26 @@ def to_dict(self, orient: str = "dict", into=dict):
  elif orient.startswith("i"):
  orient = "index"
 
- object_dtype_cols = {
- col for col, dtype in self.dtypes.items() if is_object_dtype(dtype)
- }
- are_all_object_dtype_cols = len(object_dtype_cols) == len(self.dtypes)
+ object_dtype_indices = [
+ i
+ for i, col_dtype in enumerate(self.dtypes.values)
+ if is_object_dtype(col_dtype)
+ ]
+ are_all_object_dtype_cols = len(object_dtype_indices) == len(self.dtypes)
+
  if orient == "dict":
  return into_c((k, v.to_dict(into)) for k, v in self.items())
 
  elif orient == "list":
+ object_dtype_indices = set(object_dtype_indices)
  return into_c(
  (
  k,
  list(map(maybe_box_native, v.tolist()))
- if k in object_dtype_cols
+ if i in object_dtype_indices
  else v.tolist(),
  )
- for k, v in self.items()
+ for i, (k, v) in enumerate(self.items())
  )
 
  elif orient == "split":
@@ -1935,12 +1939,9 @@ def to_dict(self, orient: str = "dict", into=dict):
  ]
  else:
  data = [list(t) for t in self.itertuples(index=False, name=None)]
- if object_dtype_cols:
- object_dtype_indices = [
- i
- for i, col in enumerate(self.columns)
- if col in object_dtype_cols
- ]
+ if object_dtype_indices:
+ # If we have object_dtype_cols, apply maybe_box_naive after list
+ # comprehension for perf
  for row in data:
  for i in object_dtype_indices:
  row[i] = maybe_box_native(row[i])
@@ -1960,12 +1961,9 @@ def to_dict(self, orient: str = "dict", into=dict):
  ]
  else:
  data = [list(t) for t in self.itertuples(index=False, name=None)]
- if object_dtype_cols:
- object_dtype_indices = [
- i
- for i, col in enumerate(self.columns)
- if col in object_dtype_cols
- ]
+ if object_dtype_indices:
+ # If we have object_dtype_cols, apply maybe_box_naive after list
+ # comprehension for perf
  for row in data:
  for i in object_dtype_indices:
  row[i] = maybe_box_native(row[i])
@@ -1998,7 +1996,13 @@ def to_dict(self, orient: str = "dict", into=dict):
  into_c(zip(columns, t))
  for t in self.itertuples(index=False, name=None)
  ]
- if object_dtype_cols:
+ if object_dtype_indices:
+ object_dtype_indices = set(object_dtype_indices)
+ object_dtype_cols = {
+ col
+ for i, col in enumerate(self.columns)
+ if i in object_dtype_indices
+ }
  for row in data:
  for col in object_dtype_cols:
  row[col] = maybe_box_native(row[col])
@@ -2013,9 +2017,10 @@ def to_dict(self, orient: str = "dict", into=dict):
  (t[0], dict(zip(self.columns, map(maybe_box_native, t[1:]))))
  for t in self.itertuples(name=None)
  )
- elif object_dtype_cols:
+ elif object_dtype_indices:
+ object_dtype_indices = set(object_dtype_indices)
  is_object_dtype_by_index = [
- col in object_dtype_cols for col in self.columns
+ i in object_dtype_indices for i in range(len(self.columns))
  ]
  return into_c(
  (