我宁愿不改变df。

一个选项是检索开始和结束日期的索引:

import numpy as np   
import pandas as pd

#Dummy DataFrame
df = pd.DataFrame(np.random.random((30, 3)))
df['date'] = pd.date_range('2017-1-1', periods=30, freq='D')

#Get the index of the start and end dates respectively
start = df[df['date']=='2017-01-07'].index[0]
end = df[df['date']=='2017-01-14'].index[0]

#Show the sliced df (from 2017-01-07 to 2017-01-14)
df.loc[start:end]

结果是:

     0   1   2       date
6  0.5 0.8 0.8 2017-01-07
7  0.0 0.7 0.3 2017-01-08
8  0.8 0.9 0.0 2017-01-09
9  0.0 0.2 1.0 2017-01-10
10 0.6 0.1 0.9 2017-01-11
11 0.5 0.3 0.9 2017-01-12
12 0.5 0.4 0.3 2017-01-13
13 0.4 0.9 0.9 2017-01-14

import pandas as pd

technologies = ({
    'Courses':["Spark","PySpark","Hadoop","Python","Pandas","Hadoop","Spark"],
    'Fee' :[22000,25000,23000,24000,26000,25000,25000],
    'Duration':['30days','50days','55days','40days','60days','35days','55days'],
    'Discount':[1000,2300,1000,1200,2500,1300,1400],
    'InsertedDates':["2021-11-14","2021-11-15","2021-11-16","2021-11-17","2021-11-18","2021-11-19","2021-11-20"]
               })
df = pd.DataFrame(technologies)
print(df)

使用pandas.DataFrame.loc按日期过滤行

方法1:

    mask = (df['InsertedDates'] > start_date) & (df['InsertedDates'] <= end_date)

    df2 = df.loc[mask]
    print(df2)

方法2:

    start_date = '2021-11-15'
    end_date = '2021-11-19'
    after_start_date = df["InsertedDates"] >= start_date
    before_end_date = df["InsertedDates"] <= end_date
    between_two_dates = after_start_date & before_end_date


    df2 = df.loc[between_two_dates]
    print(df2)

使用pandas.DataFrame.query()选择数据帧行

start_date = '2021-11-15'
end_date   = '2021-11-18'
df2 = df.query('InsertedDates >= @start_date and InsertedDates <= @end_date')
print(df2)

使用datafframe .query()选择两个日期之间的行

start_date = '2021-11-15'
end_date = '2021-11-18'
df2 = df.query('InsertedDates > @start_date and InsertedDates < @end_date')
print(df2)

pandas.Series.between()函数使用两个日期

df2 = df.loc[df["InsertedDates"].between("2021-11-16", "2021-11-18")]
print(df2)

使用DataFrame.isin()在两个日期之间选择数据帧行

df2 = df[df["InsertedDates"].isin(pd.date_range("2021-11-15", "2021-11-17"))]
print(df2)

您可以像这样在日期列上使用isin方法 df (df .isin (pd(“日期”)。date_range (start_date end_date)))

注意:这只适用于日期(正如问题所要求的)，而不适用于时间戳。

例子:

import numpy as np   
import pandas as pd

# Make a DataFrame with dates and random numbers
df = pd.DataFrame(np.random.random((30, 3)))
df['date'] = pd.date_range('2017-1-1', periods=30, freq='D')

# Select the rows between two dates
in_range_df = df[df["date"].isin(pd.date_range("2017-01-15", "2017-01-20"))]

print(in_range_df)  # print result

这给了

           0         1         2       date
14  0.960974  0.144271  0.839593 2017-01-15
15  0.814376  0.723757  0.047840 2017-01-16
16  0.911854  0.123130  0.120995 2017-01-17
17  0.505804  0.416935  0.928514 2017-01-18
18  0.204869  0.708258  0.170792 2017-01-19
19  0.014389  0.214510  0.045201 2017-01-20

你也可以用between:

df[df.some_date.between(start_date, end_date)]

有两种可能的解决方案:

使用布尔掩码，然后使用df.loc[掩码] 将日期列设置为DatetimeIndex，然后使用df[start_date: end_date]

使用布尔掩码:

确保df['date']是dtype datetime64[ns]的Series:

df['date'] = pd.to_datetime(df['date'])  

制作一个布尔掩码。Start_date和end_date可以是datetime.datetimes， np。datetime64s pd。时间戳，甚至是datetime字符串:

#greater than the start date and smaller than the end date
mask = (df['date'] > start_date) & (df['date'] <= end_date)

选择子数据帧:

df.loc[mask]

或者重新赋值给df

df = df.loc[mask]

例如,

import numpy as np
import pandas as pd

df = pd.DataFrame(np.random.random((200,3)))
df['date'] = pd.date_range('2000-1-1', periods=200, freq='D')
mask = (df['date'] > '2000-6-1') & (df['date'] <= '2000-6-10')
print(df.loc[mask])

收益率

            0         1         2       date
153  0.208875  0.727656  0.037787 2000-06-02
154  0.750800  0.776498  0.237716 2000-06-03
155  0.812008  0.127338  0.397240 2000-06-04
156  0.639937  0.207359  0.533527 2000-06-05
157  0.416998  0.845658  0.872826 2000-06-06
158  0.440069  0.338690  0.847545 2000-06-07
159  0.202354  0.624833  0.740254 2000-06-08
160  0.465746  0.080888  0.155452 2000-06-09
161  0.858232  0.190321  0.432574 2000-06-10

使用DatetimeIndex:

如果要按日期进行大量选择，则设置 首先将日期列作为索引。然后可以使用按日期选择行 df.loc [start_date: end_date]。

import numpy as np
import pandas as pd

df = pd.DataFrame(np.random.random((200,3)))
df['date'] = pd.date_range('2000-1-1', periods=200, freq='D')
df = df.set_index(['date'])
print(df.loc['2000-6-1':'2000-6-10'])

收益率

                   0         1         2
date                                    
2000-06-01  0.040457  0.326594  0.492136    # <- includes start_date
2000-06-02  0.279323  0.877446  0.464523
2000-06-03  0.328068  0.837669  0.608559
2000-06-04  0.107959  0.678297  0.517435
2000-06-05  0.131555  0.418380  0.025725
2000-06-06  0.999961  0.619517  0.206108
2000-06-07  0.129270  0.024533  0.154769
2000-06-08  0.441010  0.741781  0.470402
2000-06-09  0.682101  0.375660  0.009916
2000-06-10  0.754488  0.352293  0.339337

而Python列表索引，例如seq[start:end]包括开始，但不包括结束，相比之下，Pandas df。Loc [start_date: end_date]在结果中包含两个端点，如果它们在索引中。但是，start_date和end_date都不能在索引中。

还要注意pd。Read_csv有一个parse_dates参数，您可以使用该参数将日期列解析为datetime64s。因此，如果使用parse_dates，则不需要使用df['date'] = pd.to_datetime(df['date'])。

强烈建议将日期列转换为索引。这样做会提供很多便利。一个是很容易选择两个日期之间的行，你可以看到这个例子:

import numpy as np   
import pandas as pd

# Dataframe with monthly data between 2016 - 2020
df = pd.DataFrame(np.random.random((60, 3)))
df['date'] = pd.date_range('2016-1-1', periods=60, freq='M')

如果要选择2017-01-01到2019-01-01之间的行，只需将日期列转换为索引:

df.set_index('date', inplace=True)

然后是切片:

df.loc['2017':'2019']

你可以在直接读取csv文件时选择date列作为索引，而不是df.set_index():

df = pd.read_csv('file_name.csv',index_col='date')