add some more f-strings where useful

Author: kernc

backtesting/_plotting.py

@@ -521,7 +521,7 @@ def __eq__(self, other):
                 if arr.dtype == bool:
                     arr = arr.astype(int)
                 source.add(arr, source_name)
-                tooltips.append('@{{{}}}{{0,0.0[0000]}}'.format(source_name))
+                tooltips.append(f'@{{{source_name}}}{{0,0.0[0000]}}')
                 if is_overlay:
                     ohlc_extreme_values[source_name] = arr
                     if is_scatter:

backtesting/_util.py

@@ -111,7 +111,7 @@ def __getattr__(self, item):
         try:
             return self.__get_array(item)
         except KeyError:
-            raise AttributeError("Column '{}' not in data".format(item)) from None
+            raise AttributeError(f"Column '{item}' not in data") from None
 
     def _set_length(self, i):
         self.__i = i
@@ -125,9 +125,9 @@ def _update(self):
 
     def __repr__(self):
         i = min(self.__i, len(self.__df) - 1)
-        return '<Data i={} ({}) {}>'.format(i, self.__arrays['__index'][i],
-                                            ', '.join('{}={}'.format(k, v)
-                                                      for k, v in self.__df.iloc[i].items()))
+        index = self.__arrays['__index'][i]
+        items = ', '.join(f'{k}={v}' for k, v in self.__df.iloc[i].items())
+        return f'<Data i={i} ({index}) {items}>'
 
     def __len__(self):
         return self.__i

backtesting/backtesting.py

@@ -62,8 +62,8 @@ def __repr__(self):
         return '<Strategy ' + str(self) + '>'
 
     def __str__(self):
-        params = ','.join('{}={}'.format(*p) for p in zip(self._params.keys(),
-                                                          map(_as_str, self._params.values())))
+        params = ','.join(f'{i[0]}={i[1]}' for i in zip(self._params.keys(),
+                                                        map(_as_str, self._params.values())))
         if params:
             params = '(' + params + ')'
         return f'{self.__class__.__name__}{params}'
@@ -391,11 +391,11 @@ def __init__(self, broker: '_Broker',
 
     def _replace(self, **kwargs):
         for k, v in kwargs.items():
-            setattr(self, '_{}__{}'.format(self.__class__.__qualname__, k), v)
+            setattr(self, f'_{self.__class__.__qualname__}__{k}', v)
         return self
 
     def __repr__(self):
-        return '<Order {}>'.format(', '.join('{}={}'.format(param, round(value, 5))
+        return '<Order {}>'.format(', '.join(f'{param}={round(value, 5)}'
                                              for param, value in (
                                                  ('size', self.__size),
                                                  ('limit', self.__limit_price),
@@ -523,7 +523,7 @@ def __repr__(self):
 
     def _replace(self, **kwargs):
         for k, v in kwargs.items():
-            setattr(self, '_{}__{}'.format(self.__class__.__qualname__, k), v)
+            setattr(self, f'_{self.__class__.__qualname__}__{k}', v)
         return self
 
     def _copy(self, **kwargs):
@@ -651,7 +651,7 @@ def tp(self, price: float):
     def __set_contingent(self, type, price):
         assert type in ('sl', 'tp')
         assert price is None or 0 < price < np.inf
-        attr = '_{}__{}_order'.format(self.__class__.__qualname__, type)
+        attr = f'_{self.__class__.__qualname__}__{type}_order'
         order = getattr(self, attr)  # type: Order
         if order:
             order.cancel()