Update df hashing

tmtk/utils/filebase.py

@@ -1,11 +1,16 @@
 import os
+from hashlib import sha256
 
 import pandas as pd
 from pandas.util import hash_pandas_object
 
 from . import file2df, df2file, cached_property, Message
 
 
+def hash_df_to_single_int(df) -> int:
+    return int.from_bytes(sha256(pd.util.hash_pandas_object(df, index=True).values).digest(), 'big')
+
+
 class FileBase:
     """
     Super class with shared utilities for file objects.
@@ -25,7 +30,7 @@ def _df(self):
             Message.okay("Creating dataframe for: {}".format(self))
             df = self.create_df()
         df = self._df_processing(df)
-        self._hash_init = int(hash_pandas_object(df).sum())
+        self._hash_init = hash_df_to_single_int(df)
         return df
 
     @property
@@ -59,14 +64,14 @@ def _df_processing(self, df):
         return df
 
     def __hash__(self):
-        return int(hash_pandas_object(self.df).sum())
+        return hash_df_to_single_int(self.df)
 
     @property
     def df_has_changed(self):
         if self._hash_init is None:
             return False
         else:
-            return int(hash_pandas_object(self.df).sum()) != self._hash_init
+            return hash_df_to_single_int(self.df) != self._hash_init
 
     @property
     def header(self):