如何在熊猫中的datetime变量之前删除行？

编程问答 2022-08-13

问题描述

当我尝试选择和删除给定日期时间之前的行时，我的代码返回一个完全空的数据框。通过字符串传递datetime可以，但是我需要根据数据框的最后datetime值将其作为变量。

In:
df_transposed['Interval_Date'] = pd.to_datetime(df_transposed['Interval_Date'])
filter_range_begin = str((datetime.Now() - timedelta(hours=2)).strftime("%Y-%m-%d %H:%M:%s"))
df_transposed = df_transposed.set_index('Interval_Date')
indexNames = df_transposed[df_transposed.index.get_level_values(0) > filter_range_begin]

Out:
Empty DataFrame
Columns: [0,1,Label]
Index: []

位置：

In:
df_transposed['Interval_Date'] = pd.to_datetime(df_transposed['Interval_Date'])
filter_range_begin = '2020-09-01 02:00:00'
df_transposed = df_transposed.set_index('Interval_Date')
indexNames = df_transposed[df_transposed.index.get_level_values(0) > filter_range_begin]

返回：

Out:
                         0    1  Label
Interval_Date                          
2020-09-01 02:15:00  401121  NaN    NaN
2020-09-01 02:30:00  815314  NaN    NaN
2020-09-01 02:45:00  885369  NaN    NaN

我还需要删除任何超出此范围的行。

谢谢。

解决方法

import pandas
from datetime import datetime

df_transposed = df_transposed[df_transposed['Interval_Date'] < datetime.strptime(df_transposed['Interval_Date'].min(),'%Y-%m-%d')]

#You can put the date directly instead of df_transposed['Interval_Date'].min()
dataframedatetimedatetimedroppandasrow