Price repair improvements

Price repair improvements:
- don't attempt repair of empty prices table
- random-mixups: fix 0.01x errors, not just 100x
- stop zeroes, big-dividends, and 100x errors triggering false split errors

Author: ValueRaider

yfinance/base.py

@@ -829,6 +829,8 @@ def _reconstruct_intervals_batch(self, df, interval, prepost, tag=-1):
 
     @utils.log_indent_decorator
     def _fix_unit_mixups(self, df, interval, tz_exchange, prepost):
+        if df.empty:
+            return df
         df2 = self._fix_unit_switch(df, interval, tz_exchange)
         df3 = self._fix_unit_random_mixups(df2, interval, tz_exchange, prepost)
         return df3
@@ -842,6 +844,9 @@ def _fix_unit_random_mixups(self, df, interval, tz_exchange, prepost):
         # - a sudden switch between $<->cents at some date
         # This function fixes the first.
 
+        if df.empty:
+            return df
+
         # Easy to detect and fix, just look for outliers = ~100x local median
         logger = utils.get_yf_logger()
 
@@ -885,7 +890,11 @@ def _fix_unit_random_mixups(self, df, interval, tz_exchange, prepost):
         ratio = df2_data / median
         ratio_rounded = (ratio / 20).round() * 20  # round ratio to nearest 20
         f = ratio_rounded == 100
-        if not f.any():
+        ratio_rcp = 1.0/ratio
+        ratio_rcp_rounded = (ratio_rcp / 20).round() * 20  # round ratio to nearest 20
+        f_rcp = (ratio_rounded == 100) | (ratio_rcp_rounded == 100)
+        f_either = f | f_rcp
+        if not f_either.any():
             logger.info("price-repair-100x: No sporadic 100x errors")
             if "Repaired?" not in df.columns:
                 df["Repaired?"] = False
@@ -894,7 +903,7 @@ def _fix_unit_random_mixups(self, df, interval, tz_exchange, prepost):
         # Mark values to send for repair
         tag = -1.0
         for i in range(len(data_cols)):
-            fi = f[:, i]
+            fi = f_either[:, i]
             c = data_cols[i]
             df2.loc[fi, c] = tag
 
@@ -906,35 +915,43 @@ def _fix_unit_random_mixups(self, df, interval, tz_exchange, prepost):
         if n_after > 0:
             # This second pass will *crudely* "fix" any remaining errors in High/Low
             # simply by ensuring they don't contradict e.g. Low = 100x High.
-            f = df2_tagged
+            f = (df2[data_cols].to_numpy() == tag) & f
             for i in range(f.shape[0]):
                 fi = f[i, :]
                 if not fi.any():
                     continue
                 idx = df2.index[i]
 
-                c = "Open"
-                j = data_cols.index(c)
-                if fi[j]:
-                    df2.loc[idx, c] = df.loc[idx, c] * 0.01
-                #
-                c = "Close"
-                j = data_cols.index(c)
+                for c in ['Open', 'Close']:
+                    j = data_cols.index(c)
+                    if fi[j]:
+                        df2.loc[idx, c] = df.loc[idx, c] * 0.01
+
+                c = "High" ; j = data_cols.index(c)
                 if fi[j]:
-                    df2.loc[idx, c] = df.loc[idx, c] * 0.01
-                #
-                c = "Adj Close"
-                j = data_cols.index(c)
+                    df2.loc[idx, c] = df2.loc[idx, ["Open", "Close"]].max()
+
+                c = "Low" ; j = data_cols.index(c)
                 if fi[j]:
-                    df2.loc[idx, c] = df.loc[idx, c] * 0.01
-                #
-                c = "High"
-                j = data_cols.index(c)
+                    df2.loc[idx, c] = df2.loc[idx, ["Open", "Close"]].min()
+
+            f_rcp = (df2[data_cols].to_numpy() == tag) & f_rcp
+            for i in range(f_rcp.shape[0]):
+                fi = f_rcp[i, :]
+                if not fi.any():
+                    continue
+                idx = df2.index[i]
+
+                for c in ['Open', 'Close']:
+                    j = data_cols.index(c)
+                    if fi[j]:
+                        df2.loc[idx, c] = df.loc[idx, c] * 100.0
+
+                c = "High" ; j = data_cols.index(c)
                 if fi[j]:
                     df2.loc[idx, c] = df2.loc[idx, ["Open", "Close"]].max()
-                #
-                c = "Low"
-                j = data_cols.index(c)
+
+                c = "Low" ; j = data_cols.index(c)
                 if fi[j]:
                     df2.loc[idx, c] = df2.loc[idx, ["Open", "Close"]].min()
 
@@ -953,9 +970,9 @@ def _fix_unit_random_mixups(self, df, interval, tz_exchange, prepost):
             logger.info('price-repair-100x: ' + report_msg)
 
         # Restore original values where repair failed
-        f = df2_tagged
+        f_either = df2[data_cols].to_numpy() == tag
         for j in range(len(data_cols)):
-            fj = f[:, j]
+            fj = f_either[:, j]
             if fj.any():
                 c = data_cols[j]
                 df2.loc[fj, c] = df.loc[fj, c]
@@ -977,14 +994,6 @@ def _fix_unit_switch(self, df, interval, tz_exchange):
         # This function fixes the second.
         # Eventually Yahoo fixes but could take them 2 weeks.
 
-        # To detect, use 'bad split adjustment' algorithm. But only correct
-        # if no stock splits in data
-
-        f_splits = df['Stock Splits'].to_numpy() != 0.0
-        if f_splits.any():
-            utils.get_yf_logger().debug('price-repair-100x: Cannot check for chunked 100x errors because splits present')
-            return df
-
         return self._fix_prices_sudden_change(df, interval, tz_exchange, 100.0)
 
     @utils.log_indent_decorator
@@ -993,6 +1002,9 @@ def _fix_zeroes(self, df, interval, tz_exchange, prepost):
         # But most times when prices=0 or NaN returned is because no trades.
         # Impossible to distinguish, so only attempt repair if few or rare.
 
+        if df.empty:
+            return df
+
         logger = utils.get_yf_logger()
 
         if df.shape[0] == 0:
@@ -1101,6 +1113,9 @@ def _fix_missing_div_adjust(self, df, interval, tz_exchange):
         # Easy to detect and correct BUT ONLY IF the data 'df' includes today's dividend.
         # E.g. if fetching historic prices before todays dividend, then cannot fix.
 
+        if df.empty:
+            return df
+
         logger = utils.get_yf_logger()
 
         if df is None or df.empty:
@@ -1173,6 +1188,9 @@ def _fix_bad_stock_split(self, df, interval, tz_exchange):
         # which direction to reverse adjustment - have to analyse prices and detect. 
         # Not difficult.
 
+        if df.empty:
+            return df
+            
         logger = utils.get_yf_logger()
 
         interday = interval in ['1d', '1wk', '1mo', '3mo']
@@ -1198,6 +1216,9 @@ def _fix_bad_stock_split(self, df, interval, tz_exchange):
 
     @utils.log_indent_decorator
     def _fix_prices_sudden_change(self, df, interval, tz_exchange, change, correct_volume=False):
+        if df.empty:
+            return df
+            
         logger = utils.get_yf_logger()
 
         df = df.sort_index(ascending=False)
@@ -1262,11 +1283,25 @@ def _fix_prices_sudden_change(self, df, interval, tz_exchange, change, correct_v
             # Avoid using 'Low' and 'High'. For multiday intervals, these can be 
             # very volatile so reduce ability to detect genuine stock split errors
             _1d_change_x = np.full((n, 2), 1.0)
-            price_data = df2[['Open','Close']].replace(0.0, 1.0).to_numpy()
+            price_data = df2[['Open','Close']].to_numpy()
+            f_zero = price_data == 0.0
         else:
             _1d_change_x = np.full((n, 4), 1.0)
-            price_data = df2[OHLC].replace(0.0, 1.0).to_numpy()
+            price_data = df2[OHLC].to_numpy()
+            f_zero = price_data == 0.0
+        if f_zero.any():
+            price_data[f_zero] = 1.0
+
+        # Update: if a VERY large dividend is paid out, then can be mistaken for a 1:2 stock split.
+        # Fix = use adjusted prices
+        adj = df2['Adj Close'].to_numpy() / df2['Close'].to_numpy()
+        for j in range(price_data.shape[1]):
+            price_data[:,j] *= adj
+
         _1d_change_x[1:] = price_data[1:, ] / price_data[:-1, ]
+        f_zero_num_denom = f_zero | np.roll(f_zero, 1, axis=0)
+        if f_zero_num_denom.any():
+            _1d_change_x[f_zero_num_denom] = 1.0
         if interday and interval != '1d':
             # average change
             _1d_change_minx = np.average(_1d_change_x, axis=1)
@@ -1365,6 +1400,29 @@ def _fix_prices_sudden_change(self, df, interval, tz_exchange, change, correct_v
             logger.info(f'price-repair-split: No {fix_type}s detected')
             return df
 
+        # Update: if any 100x changes are soon after a stock split, so could be confused with split error, then abort
+        threshold_days = 30
+        f_splits = df['Stock Splits'].to_numpy() != 0.0
+        if change in [100.0, 0.01] and f_splits.any():
+            indices_A = np.where(f_splits)[0]
+            indices_B = np.where(f)[0]
+            if not len(indices_A) or not len(indices_B):
+                return None
+            gaps = indices_B[:, None] - indices_A
+            # Because data is sorted in DEscending order, need to flip gaps
+            gaps *= -1
+            f_pos = gaps > 0
+            if f_pos.any():
+                gap_min = gaps[f_pos].min()
+                gap_td = utils._interval_to_timedelta(interval) * gap_min
+                if isinstance(gap_td, _dateutil.relativedelta.relativedelta):
+                    threshold = _dateutil.relativedelta.relativedelta(days=threshold_days)
+                else:
+                    threshold = _datetime.timedelta(days=threshold_days)
+                if gap_td < threshold:
+                    logger.info(f'price-repair-split: 100x changes are too soon after stock split events, aborting')
+                    return df
+
         # if logger.isEnabledFor(logging.DEBUG):
         #     df_debug['i'] = list(range(0, df_debug.shape[0]))
         #     df_debug['i_rev'] = df_debug.shape[0]-1 - df_debug['i']