Slice pandas dataframe based on datetime column

问题

I have a pandas dataframe with a column as datatime that looks like:

data.ts_placed
Out[68]: 
1         2008-02-22 15:30:40
2         2008-03-20 16:56:00
3         2008-06-14 21:26:02
4         2008-06-16 10:26:02
5         2008-06-23 20:41:03
6         2008-07-17 08:02:00
7         2008-10-13 12:47:05
8         2008-11-14 09:20:33
9         2009-02-23 11:24:18
10        2009-03-02 10:29:19

I'd like to slice the dataframe by eliminating all rows before 2009

回答1:

You can use a simple string comparison to compare the values against a year string:

In [63]:
df.loc[df['date'] >= '2009']

Out[63]:
                     date
index                    
9     2009-02-23 11:24:18
10    2009-03-02 10:29:19

Or use the dt attribute to access the year:

In [64]:
df.loc[df['date'].dt.year >= 2009]

Out[64]:
                     date
index                    
9     2009-02-23 11:24:18
10    2009-03-02 10:29:19

来源：https://stackoverflow.com/questions/31878699/slice-pandas-dataframe-based-on-datetime-column