[Python] How to deal with SettingWithCopyWarning in Pandas

I just upgraded my Pandas from 0.11 to 0.13.0rc1. Now, the application is popping out many new warnings. One of them like this:

E:\FinReporter\FM_EXT.py:449: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_index,col_indexer] = value instead
quote_df['TVol'] = quote_df['TVol']/TVOL_SCALE


What exactly does it mean? Do I need to change something?

How should I suspend the warning if I insist on using quote_df['TVol'] = quote_df['TVol']/TVOL_SCALE?

The function that gives warnings


def _decode_stock_quote(list_of_150_stk_str):
"""decode the webpage and return dataframe"""

from cStringIO import StringIO

str_of_all = "".join(list_of_150_stk_str)

quote_df = pd.read_csv(
StringIO(str_of_all),
sep=',',
names=list('ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefg'))
#dtype={'A': object, 'B': object, 'C': np.float64}
quote_df.rename(
columns={
'A':'STK', 'B':'TOpen', 'C':'TPCLOSE', 'D':'TPrice',
'E':'THigh', 'F':'TLow', 'I':'TVol', 'J':'TAmt',
'e':'TDate', 'f':'TTime'},
inplace=True)
quote_df = quote_df.ix[:,[0,3,2,1,4,5,8,9,30,31]]
quote_df['TClose'] = quote_df['TPrice']
quote_df['RT'] = 100 * (quote_df['TPrice']/quote_df['TPCLOSE'] - 1)
quote_df['TVol'] = quote_df['TVol']/TVOL_SCALE
quote_df['TAmt'] = quote_df['TAmt']/TAMT_SCALE
quote_df['STK_ID'] = quote_df['STK'].str.slice(13,19)
quote_df['STK_Name'] = quote_df['STK'].str.slice(21,30)#.decode('gb2312')
quote_df['TDate'] = quote_df.TDate.map(lambda x: x[0:4]+x[5:7]+x[8:10])

return quote_df

More warning messages


E:\FinReporter\FM_EXT.py:449: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_index,col_indexer] = value instead
quote_df['TVol'] = quote_df['TVol']/TVOL_SCALE
E:\FinReporter\FM_EXT.py:450: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_index,col_indexer] = value instead
quote_df['TAmt'] = quote_df['TAmt']/TAMT_SCALE
E:\FinReporter\FM_EXT.py:453: SettingWithCopyWarning: A value is trying to be set on a copy of a slice from a DataFrame.
Try using .loc[row_index,col_indexer] = value instead
quote_df['TDate'] = quote_df.TDate.map(lambda x: x[0:4]+x[5:7]+x[8:10])

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