Q:

Fixing Apparent Anaconda Python Corruption Fix

I am developing in Windows 7.0 Professional using Anaconda Python 2.7 in Spyder 3.1.4.  I am also using Pandas. 
After considerable work on a program I got a consistent strange problem.   Python / Pandas started treating two identical dataframes with different names the same way.  
I defined the dataframes as follows:
dfa = pd. DataFrame(np.empty(0,dtype=[('Date','datetime64[ns]'),
                                    ('column1', 'string'),
                                    ('column2','string'),
                                    ('column3','string')]))

I now duplicate this (empty) dataframe:
dfb = dfa

Just after this I append to dfa as follows:
dfa.loc[indexvalue,:] = ([item1,item2,item3....])

This worked properly until after many runs involved (to test other parts of the code) this command ALSO started identically updating dfb at the same time.   Similar operations using dfb results in identical updates to dfa
I am not an expert at package installation and have extensively examined my code.   This appears to be a corruption. 
Can someone advise on how best to handle this?   I don't want to start ripping apart my Anaconda installation.   If this is indeed a corruption on the environment, what is the best way to repair/reinstall Anaconda and Spyder? 
Thanks in advance. 

A:

dfb = dfa just sets to variable to point to the same object.   If you update dfa you are updating the same object as dfb.  This is how Pandas works. 
If you really want to create a copy of dfa use:
dfc = dfa.copy()

How do you check to see if your variable is point a copy of the dataframe of is it pointed to the same dataframe:
dfb is dfa
True

dfc is dfa
False

This is not corruption.