Fix Yahoo! price data

Adds back support for downloading price data from Yahoo!

Author: Noah Stoffman

docs/source/whatsnew/v0.7.0.txt

@@ -54,4 +54,5 @@ Bug Fixes
 - Handle Morningstar index volume data properly (:issue:`486`).
 - Added support for optionally passing a custom base_url to the EnigmaReader  (:issue:`499`).
 - Fixed Morningstar 'retry' incrementation (:issue:`513`)
-- Updated Google Daily Price API to functional url (:issue:`502`)
+- Updated Google Daily Price API to functional url (:issue:`502`)
+- Fix Yahoo! price data (:issue:`498`)

pandas_datareader/yahoo/daily.py

@@ -125,16 +125,16 @@ def _read_one_data(self, url, params):
         ptrn = r'root\.App\.main = (.*?);\n}\(this\)\);'
         jsn = json.loads(re.search(ptrn, resp.text, re.DOTALL).group(1))
         df = DataFrame(
-                jsn['context']['dispatcher']['stores']
-                ['HistoricalPriceStore']['prices']
-                )
+            jsn['context']['dispatcher']['stores']
+            ['HistoricalPriceStore']['prices']
+        )
         df['date'] = to_datetime(df['date'], unit='s').dt.date
         df = df.dropna(subset=['close'])
         df = df[['date', 'high', 'low', 'open', 'close',
                  'volume', 'adjclose']]
 
         if self.ret_index:
-            df['Ret_Index'] = _calc_return_index(df['adjclose'])
+            df['Ret_Index'] = _calc_return_index(df['Adj Close'])
         if self.adjust_price:
             df = _adjust_prices(df)
         return df.sort_index().dropna(how='all')