Python：创建自定义 pd.dataframe 类

Question

我想为熊猫数据框放置一些标准任务，例如用数据初始化并将这些数据处理到一个类中。 我目前正在执行以下示例步骤：

import pandas as pd
import urllib.request


def __get_data():
    URL = r'https://en.wikipedia.org/wiki/List_of_sovereign_states_' \
          r'and_dependent_territories_by_continent_(data_file)#Data_file'
    HTML_STRING = urllib.request.urlopen(URL)
    return pd.read_html(HTML_STRING)[2]


def __prepare_data(df):
    df.iloc[:,-1] = df.iloc[:,-1].str.upper()
    return df


MyDataFrame = pd.DataFrame()
MyDataFrame = __get_data()
MyDataFrame = __prepare_data(MyDataFrame)

我想要这样的东西：

class MyDataFrame(pd.DataFrame):
    def __init__(self, *args, **kwargs):
        super(MyDataFrame, self).__init__(*args, **kwargs)
        self = self.__get_data()
        self.__prepare_data()

    def __get_data(self):
        URL = r'https://en.wikipedia.org/wiki/List_of_sovereign_states_' \
              r'and_dependent_territories_by_continent_(data_file)#Data_file'
        HTML_STRING = urllib.request.urlopen(URL)
        return pd.read_html(HTML_STRING)[2]

    def __prepare_data(self):
        self.iloc[:, -1] = self.iloc[:, -1].str.upper()

不幸的是，我不了解这种情况下的Pandas 文档。

Answer 1

虽然我认为这是不明智的，但这种修改有效：

class MyDataFrame(pd.DataFrame):
    def __init__(self, *args, **kwargs):
        super(MyDataFrame, self).__init__(*args, **kwargs)
        self.data = self.__get_data()
        self.__prepare_data()

    def __get_data(self):
        URL = r'https://en.wikipedia.org/wiki/List_of_sovereign_states_' \
              r'and_dependent_territories_by_continent_(data_file)#Data_file'
        HTML_STRING = urllib.request.urlopen(URL)
        return pd.read_html(HTML_STRING)[2]

    def __prepare_data(self):
        self.data.iloc[:, -1] = self.data.iloc[:, -1].str.upper()

d = MyDataFrame()

print(d.data)

输出：

    CC  a-2 a-3     #       Name
0   AS  AF  AFG     4.0     AFGHANISTAN, ISLAMIC REPUBLIC OF
1   EU  AL  ALB     8.0     ALBANIA, REPUBLIC OF
2   AN  AQ  ATA     10.0    ANTARCTICA (THE TERRITORY SOUTH OF 60 DEG S)
3   AF  DZ  DZA     12.0    ALGERIA, PEOPLES DEMOCRATIC REPUBLIC OF
4   OC  AS  ASM     16.0    AMERICAN SAMOA
...     ...     ...     ...     ...     ...
257     AF  ZM  ZMB 894.0   ZAMBIA, REPUBLIC OF
258     AS  XD  NaN NaN     UNITED NATIONS NEUTRAL ZONE
259     AS  XE  NaN NaN     IRAQ-SAUDI ARABIA NEUTRAL ZONE
260     AS  XS  NaN NaN     SPRATLY ISLANDS
261     OC  XX  NaN NaN     DISPUTED TERRITORY