From a5591b28c3a7ec4f025359ffba3aa9149d4fdc99 Mon Sep 17 00:00:00 2001
From: Darin Plutchok <dplutchok@techtarget.com>
Date: Tue, 3 Dec 2019 15:35:07 -0800
Subject: [PATCH] f-string update for core.base.

---
 pandas/core/base.py | 27 ++++++++-------------------
 1 file changed, 8 insertions(+), 19 deletions(-)

diff --git a/pandas/core/base.py b/pandas/core/base.py
index 066a7628be364..5e613849ba8d5 100644
--- a/pandas/core/base.py
+++ b/pandas/core/base.py
@@ -114,9 +114,7 @@ def __setattr__(self, key, value):
             or key in type(self).__dict__
             or getattr(self, key, None) is not None
         ):
-            raise AttributeError(
-                "You cannot add any new attribute '{key}'".format(key=key)
-            )
+            raise AttributeError(f"You cannot add any new attribute '{key}'")
         object.__setattr__(self, key, value)
 
 
@@ -220,28 +218,22 @@ def _obj_with_exclusions(self):
 
     def __getitem__(self, key):
         if self._selection is not None:
-            raise IndexError(
-                "Column(s) {selection} already selected".format(
-                    selection=self._selection
-                )
-            )
+            raise IndexError(f"Column(s) {self._selection} already selected")
 
         if isinstance(key, (list, tuple, ABCSeries, ABCIndexClass, np.ndarray)):
             if len(self.obj.columns.intersection(key)) != len(key):
                 bad_keys = list(set(key).difference(self.obj.columns))
-                raise KeyError(
-                    "Columns not found: {missing}".format(missing=str(bad_keys)[1:-1])
-                )
+                raise KeyError(f"Columns not found: {str(bad_keys)[1:-1]}")
             return self._gotitem(list(key), ndim=2)
 
         elif not getattr(self, "as_index", False):
             if key not in self.obj.columns:
-                raise KeyError("Column not found: {key}".format(key=key))
+                raise KeyError(f"Column not found: {key}")
             return self._gotitem(key, ndim=2)
 
         else:
             if key not in self.obj:
-                raise KeyError("Column not found: {key}".format(key=key))
+                raise KeyError(f"Column not found: {key}")
             return self._gotitem(key, ndim=1)
 
     def _gotitem(self, key, ndim, subset=None):
@@ -293,8 +285,7 @@ def _try_aggregate_string_function(self, arg: str, *args, **kwargs):
                 return f(self, *args, **kwargs)
 
         raise AttributeError(
-            "'{arg}' is not a valid function for "
-            "'{cls}' object".format(arg=arg, cls=type(self).__name__)
+            f"'{arg}' is not a valid function for '{type(self).__name__}' object"
         )
 
     def _aggregate(self, arg, *args, **kwargs):
@@ -359,7 +350,7 @@ def _aggregate(self, arg, *args, **kwargs):
                     elif isinstance(obj, ABCSeries):
                         raise SpecificationError("nested renamer is not supported")
                     elif isinstance(obj, ABCDataFrame) and k not in obj.columns:
-                        raise KeyError("Column '{col}' does not exist!".format(col=k))
+                        raise KeyError(f"Column '{k}' does not exist!")
 
                 arg = new_arg
 
@@ -1101,9 +1092,7 @@ def _reduce(
         func = getattr(self, name, None)
         if func is None:
             raise TypeError(
-                "{klass} cannot perform the operation {op}".format(
-                    klass=type(self).__name__, op=name
-                )
+                f"{type(self).__name__} cannot perform the operation {name}"
             )
         return func(skipna=skipna, **kwds)