如何使用dataframe between_time（）函数

问题描述

我正在尝试使用 between_time 函数。我将格式化字符串类型时间到datetime

I am trying to use the between_time function. I have formatted the string type time to datetime

dataset['TimeStamp'] = pd.to_datetime(dataset['TimeStamp'],format)

我定义了搜索开始时间和结束时间：

and I defined search start time and end time:

start = datetime.time(9,40,0)

end = datetime.time(10,00,0)

然后我调用 dataset ['TimeStamp']。between_time（start，end） / code>

then I call dataset['TimeStamp'].between_time(start, end)

这是我得到的错误：

TypeError: Index must be DatetimeIndex

请问如何解决它。谢谢

推荐答案

示例 - 我使用来自评论的信息：

Example - I use info from comments:

import pandas as pd
import StringIO
import datetime

data = '''time --- value
1984-12-12 14:08:00 --- 1
1984-12-12 14:25:00 --- 2
1984-12-12 14:47:00 --- 4
1984-12-12 16:37:00 --- 3
1984-12-12 16:37:00 --- 9
1984-12-12 16:37:00 --- 5
1984-12-12 17:52:00 --- 3
1984-12-12 17:52:00 --- 7
1984-12-12 19:29:00 --- 2'''

#------------------------------------------------

df = pd.read_csv(StringIO.StringIO(data), sep=' --- ')

df['time'] = pd.DatetimeIndex(df['time'])

print "\nDataFrame:\n", df 

print '\nIndex:', type(df.index)

#------------------------------------------------

df.set_index(keys='time', inplace=True)

print "\nDataFrame:\n", df 

print '\nIndex:', type(df.index)

#------------------------------------------------

start = datetime.time(14,50,0)
end = datetime.time(18,0,0)

print "\nResult:\n", df['value'].between_time(start, end)

结果：

DataFrame:
                 time  value
0 1984-12-12 14:08:00      1
1 1984-12-12 14:25:00      2
2 1984-12-12 14:47:00      4
3 1984-12-12 16:37:00      3
4 1984-12-12 16:37:00      9
5 1984-12-12 16:37:00      5
6 1984-12-12 17:52:00      3
7 1984-12-12 17:52:00      7
8 1984-12-12 19:29:00      2

Index: <class 'pandas.core.index.Int64Index'>

DataFrame:
                     value
time                      
1984-12-12 14:08:00      1
1984-12-12 14:25:00      2
1984-12-12 14:47:00      4
1984-12-12 16:37:00      3
1984-12-12 16:37:00      9
1984-12-12 16:37:00      5
1984-12-12 17:52:00      3
1984-12-12 17:52:00      7
1984-12-12 19:29:00      2

Index: <class 'pandas.tseries.index.DatetimeIndex'>

Result:
time
1984-12-12 16:37:00    3
1984-12-12 16:37:00    9
1984-12-12 16:37:00    5
1984-12-12 17:52:00    3
1984-12-12 17:52:00    7
Name: value, dtype: int64

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