如何从列表中找出列中所有单元格中都缺少两种货币的货币对？

Question

假设您有一个名为currency_trading_pairs的列表，其中包含以下元素：

currency_trading_pairs = ['USD/CAD', 'EUR/USD', 'GBP/USD', 'NZD/USD', 'AUD/USD', 
                          'USD/JPY', 'EUR/CAD', 'EUR/AUD', 'EUR/JPY', 'EUR/GBP',
                          'AUD/CAD', 'GBP/JPY', 'CHF/JPY', 'AUD/JPY', 'AUD/NZD']

现在，假设您有以下数据，名为filtered_df，具有以下数据：

    Time    Currency    Volatility expected        Event
24  04:30     GBP   Low Volatility Expected        Inflation Expectations
25  05:00     EUR   High Volatility Expected       EU Leaders Summit  
26  05:10     EUR   Low Volatility Expected        Italian 15-Year BTP Auction
27  05:10     EUR   Low Volatility Expected        Italian 3-Year BTP Auction
28  05:10     EUR   Low Volatility Expected        Italian 7-Year BTP Auction
29  06:00     EUR   Low Volatility Expected        Spanish Consumer Confidence
30  06:30     INR   Low Volatility Expected        Bank Loan Growth
31  06:30     INR   Low Volatility Expected        Deposit Growth
32  06:30     INR   Low Volatility Expected        FX Reserves, USD
33  07:00     INR   Low Volatility Expected        Cumulative Industrial Production (Jan)
34  07:00     INR   Low Volatility Expected        Industrial Production (YoY) (Jan)
35  07:00     INR   Low Volatility Expected        Manufacturing Output (MoM) (Jan)
36  07:00     BRL   Moderate Volatility Expected   CPI (YoY) (Feb)
37  07:00     BRL   Moderate Volatility Expected   CPI (MoM) (Feb)
38  08:06     BRL   Moderate Volatility Expected   Brazilian IPCA Inflation Index SA (MoM)(Feb)
39  08:30     CAD   Low Volatility Expected        Capacity Utilization Rate (Q4)
40  08:30     CAD   High Volatility Expected       Employment Change (Feb)
41  08:30     CAD   Low Volatility Expected        Full Employment Change (Feb)
42  08:30     CAD   Low Volatility Expected        Part Time Employment Change (Feb)
43  08:30     CAD   Low Volatility Expected        Participation Rate (Feb)
44  08:30     CAD   Moderate Volatility Expected   Unemployment Rate (Feb)

如何从currency_trading_pairs (列表)中找到Currency列中的所有单元格中缺少两种货币的货币对(元素)，以便在名为the_missing_pairs的变量中获得以下输出

the_missing_pairs = ['NZD/USD', 'AUD/USD', 'USD/JPY', 'CHF/JPY', 'AUD/JPY', 'AUD/NZD']

进一步解释:基本上，确保the_missing_pairs列表中的所有货币名称都不会出现在来自filtered_df的列Currency中的任何单元格中。

Answer 1

实际上，我会将currency_trading_pairs转换为Series。然后您可以使用/和explode拆分，然后使用isin，最后使用groupby(level=0) + any来生成完美的掩码：

ctp = pd.Series(currency_trading_pairs)
the_missing_pairs = ctp[~ctp.str.split('/').explode().isin(df['Currency']).groupby(level=0).any()].tolist()

输出：

>>> the_missing_pairs
['NZD/USD', 'AUD/USD', 'USD/JPY', 'CHF/JPY', 'AUD/JPY', 'AUD/NZD']