pandas dataframe 中的索引时间戳问题

Question

I have a pandas dataframe which reads from a csv file and has a timestamp column. I am trying to get the rows that were in the last 3 hours. So far I have:

 df_trade = pd.read_csv("log.csv")
 df_ma.set_index('timestamp')
 start = format_time()
 end = start - pd.Timedelta(hours=3)
 df_ma = df_ma[end:]

This is my helper function:

def format_time():
    t = datetime.now()
    s = t.strftime('%Y-%m-%d %H:%M:%S')
    return pd.to_datetime(s)

However, I get this error when I try to do slicing:

TypeError: cannot do slice indexing on RangeIndex with these indexers [2021-06-01 07:07:53] of type Timestamp

How can I resolve this issue

Answer 1

You have to change your last line:

df_ma = df_ma[end:]

become

df_ma = df_ma.loc[df_ma.index > end]