Open     High      Low    Close AdjClose    Volume
datetime                                                         
2018-07-27  28.8200  29.3350  27.7050  28.1300  28.1300   8101362
2018-07-26  28.4800  29.1200  27.5500  28.9800  28.9800  10582061
2018-07-25  30.0900  30.0900  28.4800  28.9800  28.9800   9801897
2018-07-24  30.4500  30.9400  29.9650  30.1400  30.1400   5706941
2018-07-23  31.1100  31.3500  30.6000  30.8200  30.8200   6023310                  

A=pd.DataFrame(df)
print (A.head(5))
Len=len(A)
print (Len)
for Rw in range(Len-1):
    def adj(A):
        BB=float(A.iloc[Rw,4])
        CC=float(A.iloc[Rw+1,4])
        #print (BB,CC)
        if BB>CC:
            x1=BB-CC
            print(x1,x2)
        else:
            x2=CC-BB
            print(x1,x2)
        A.at[Rw+1,'Up']=x1   #Store calculation results in Up column
        A.at[Rw+1,'Down']=x2 #Store calculation results in Down column  
    adj(A)
print(A.head(5))

Traceback (most recent call last):
  File "D:\Yossi\eclipse-workspace_yossi\Tests\to_forum___003.py", line 85, in <module>
    adj(A)
  File "D:\Yossi\eclipse-workspace_yossi\Tests\to_forum___003.py", line 82, in adj
    A.at[Rw+1,'Up']=x1      #Store calculation results in UpMv columns
  File "C:\Python27\lib\site-packages\pandas\core\indexing.py", line 2159, in __setitem__
    self.obj._set_value(*key, takeable=self._takeable)
  File "C:\Python27\lib\site-packages\pandas\core\frame.py", line 2587, in _set_value
    self.loc[index, col] = value
  File "C:\Python27\lib\site-packages\pandas\core\indexing.py", line 189, in __setitem__
    self._setitem_with_indexer(indexer, value)
  File "C:\Python27\lib\site-packages\pandas\core\indexing.py", line 375, in _setitem_with_indexer
    labels = index.insert(len(index), key)