Python3.x 在 Python 中比较和排序列之间的值(带有不匹配列)

现在开始(尽管我必须补充说，这个解决方案相当麻烦，因为Pandas DataFrame应该表达不同列之间的关系，而这里所做的没有任何关系):

import pandas as pd

data = {'Big List': [10,2,15,17,30,40,45,47,50], 'Small List': [17,15,42,31,45,30, None, None, None]}
df = pd.DataFrame(data)
new_df = df[['Big List']].merge(df[['Small List']], left_on='Big List', right_on='Small List', how='left')
new_df.sort_values(by='Big List', inplace=True)
notfound_df = df[['Big List']].merge(df[['Small List']], left_on='Big List', right_on='Small List', how='right')
notfound_df = notfound_df[notfound_df['Big List'].isna()].dropna(how='all')
notfound_list = notfound_df['Small List'].to_list()
for i in range(new_df.shape[0] - len(notfound_list)):
    notfound_list.append(None)
new_df = pd.concat([new_df, pd.DataFrame(notfound_list, columns=['Not Matched to Big List'])], axis=1)
new_df

   Big List  Small List  Not Matched to Big List
1         2         NaN                     31.0
0        10         NaN                     42.0
2        15        15.0                      NaN
3        17        17.0                      NaN
4        30        30.0                      NaN
5        40         NaN                      NaN
6        45        45.0                      NaN
7        47         NaN                      NaN
8        50         NaN                      NaN