Q:

How to remove some string value in timestamp

I have dataframe column timestamp is string format 
2016-03-29 23:29:14 +0000. 
How can keep only 2016-03-29 23:29:14.?

A:

If the original timestamp column is of type string, then you can proceed as follows:
In [2]: df
Out[2]: 
                   timestamp
0  2016-03-29 23:29:14 +0000

In [3]: pd.to_datetime(df.timestamp).astype(str)
Out[3]: 
0    2016-03-29 23:29:14
Name: timestamp, dtype: object

