在 pandas 中使用重新索引而不更改其他列数据

Question

这是我的代码，我正在尝试将数据帧的索引值更改为数据帧中存在的日期。

import pandas as pd

x = {
    'Dates':['24/09/1998', '26/01/1999', '28/08/1999', '11/09/1999'],
    'Names': ['A', "B", 'C', 'D'],
    'Marks': [5, 8, 5, 9],
    'City': ['Rjy', 'Nzmbd', 'Kurnool', 'Srk']}

df = pd.DataFrame(x)
df['Dates']=pd.to_datetime(df['Dates'])
dt = df['Dates']
idx = pd.DatetimeIndex(dt)
df = df.reindex(idx)
print(df)

我得到的输出数据帧是，

              Dates Names  Marks City
    1998-01-01   NaT   NaN    NaN  NaN

    1998-01-02   NaT   NaN    NaN  NaN

    1998-01-03   NaT   NaN    NaN  NaN

    1998-01-04   NaT   NaN    NaN  NaN

    1998-01-05   NaT   NaN    NaN  NaN

我应该在我的代码中更改什么以使我的数据不会更改为 NaN 或 NaT？

Answer 1

我会这样做：

x = {

'Dates':['24/09/1998', '26/01/1999', '28/08/1999', '11/09/1999'],
'Names': ['A', "B", 'C', 'D'],
'Marks': [5, 8, 5, 9],
'City': ['Rjy', 'Nzmbd', 'Kurnool', 'Srk']}
df = pd.DataFrame(x)


df = df.set_index('Dates')
df.index = pd.to_datetime(df.index)

print(df)
print('\n')
df.info()

输出：

           Names  Marks     City
Dates                           
1998-09-24     A      5      Rjy
1999-01-26     B      8    Nzmbd
1999-08-28     C      5  Kurnool
1999-11-09     D      9      Srk

<class 'pandas.core.frame.DataFrame'>
DatetimeIndex: 4 entries, 1998-09-24 to 1999-11-09
Data columns (total 3 columns):
Names    4 non-null object
Marks    4 non-null int64
City     4 non-null object
dtypes: int64(1), object(2)
memory usage: 128.0+ bytes

Answer 2

你可以试试这个：

In [1]:
## Set the Dataframe
x = {
    'Dates':['24/09/1998', '26/01/1999', '28/08/1999', '11/09/1999'],
    'Names': ['A', "B", 'C', 'D'],
    'Marks': [5, 8, 5, 9],
    'City': ['Rjy', 'Nzmbd', 'Kurnool', 'Srk']
    }
df = pd.DataFrame(x)

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

# Change the index
df = df.set_index('Dates')
df

Out [1]:

              Names   Marks     City
Dates           
1998-09-24      A       5       Rjy
1999-01-26      B       8       Nzmbd
1999-08-28      C       5       Kurnool
1999-11-09      D       9       Srk

在 pandas 中使用重新索引而不更改其他列数据

Using reindex in pandas without changing other column data

python

pandas

reindex