获取 DataFrame 列中最后一场比赛的索引

Question

我有一个 dataframe，trans_df，股票买卖交易。 我正在尝试创建一个总计所有以前交易的列和另一个将当前交易添加到这个累积的以前交易金额的列。

我的输入 df 如下所示：

 <p>&nbsp;</p> <table style="border: none;border-collapse: collapse;width:194pt;"> <tbody> <tr> <td style="color:black;font-size:15px;font-weight:700;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:top;border:.5pt solid windowtext;height:14.4pt;width:98pt;">date</td> <td style="color:black;font-size:15px;font-weight:700;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:top;border:.5pt solid windowtext;border-left:none;width:48pt;">ticker</td> <td style="color:black;font-size:15px;font-weight:700;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:top;border:.5pt solid windowtext;border-left:none;width:48pt;">quantity</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2020-01-08</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">MMM</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">1</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2020-01-08</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">RUN</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">10</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2020-01-09</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">AAPL</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">10</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2020-02-10</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">RUN</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">20</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2020-03-16</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">MMM</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">2</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2021-01-09</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">F</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">5</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2021-01-10</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">MMM</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">3</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2021-01-11</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">RUN</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">30</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2021-01-12</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">RUN</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">-5</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2021-01-13</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">AAPL</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">-5</td> </tr> <tr> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:general;vertical-align:bottom;border:none;text-align:center;height:14.4pt;">2021-01-14</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:center;vertical-align:bottom;border:none;">MMM</td> <td style="color:black;font-size:15px;font-weight:400;font-style:normal;text-decoration:none;font-family:Calibri, sans-serif;text-align:right;vertical-align:bottom;border:none;">6</td> </tr> </tbody> </table>

我最终想要的是：

 <table style="border: none;width:373.0pt;margin-left:-.05pt;border-collapse:collapse;"> <tbody> <tr> <td style="width: 98pt;border: 1pt solid windowtext;padding: 0in 5.4pt;height: 0.2in;vertical-align: top;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:center;'><strong><span style="color:black;">date</span></strong></p> </td> <td style="width: 48pt;border-color: windowtext windowtext windowtext currentcolor;border-style: solid solid solid none;border-width: 1pt 1pt 1pt medium;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 0.2in;vertical-align: top;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:center;'><strong><span style="color:black;">ticker</span></strong></p> </td> <td style="width: 48pt;border-color: windowtext windowtext windowtext currentcolor;border-style: solid solid solid none;border-width: 1pt 1pt 1pt medium;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 0.2in;vertical-align: top;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:center;'><strong><span style="color:black;">quantity</span></strong></p> </td> <td style="width: 77pt;border-color: windowtext windowtext windowtext currentcolor;border-style: solid solid solid none;border-width: 1pt 1pt 1pt medium;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 0.2in;vertical-align: top;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:center;'><strong><span style="color:black;">last_entry</span></strong></p> </td> <td style="width: 53pt;border-color: windowtext windowtext windowtext currentcolor;border-style: solid solid solid none;border-width: 1pt 1pt 1pt medium;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 0.2in;vertical-align: top;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:center;'><strong><span style="color:black;">prev_units</span></strong></p> </td> <td style="width: 49pt;border-color: windowtext windowtext windowtext currentcolor;border-style: solid solid solid none;border-width: 1pt 1pt 1pt medium;border-image: none 100% / 1 / 0 stretch;padding: 0in 5.4pt;height: 0.2in;vertical-align: top;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:center;'><strong><span style="color:black;">cml_units</span></strong></p> </td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2020-01-08</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">MMM</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">1</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"><br></td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">0</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">1</span></p> </td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2020-01-08</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">RUN</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">10</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"><br></td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">0</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">5</span></p> </td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2020-01-09</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">AAPL</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">10</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"><br></td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">0</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">10</span></p> </td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2020-02-10</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">RUN</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">20</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">1</span></p> </td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">5</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">25</span></p> </td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2020-03-16</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">MMM</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">0</span></p> </td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">1</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">3</span></p> </td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2021-01-09</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">F</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">5</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"><br></td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">0</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"><br></td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2021-01-10</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">MMM</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">3</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">5</span></p> </td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">3</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">6</span></p> </td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2021-01-11</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">RUN</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">30</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">4</span></p> </td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">25</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">55</span></p> </td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2021-01-12</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">RUN</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">-5</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">8</span></p> </td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">55</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">50</span></p> </td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2021-01-13</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">AAPL</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">-5</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2</span></p> </td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">10</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">5</span></p> </td> </tr> <tr> <td style="width: 98pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">2021-01-14</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;'><span style="color:black;">MMM</span></p> </td> <td style="width: 48pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">6</span></p> </td> <td style="width: 77pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">7</span></p> </td> <td style="width: 53pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">6</span></p> </td> <td style="width: 49pt;padding: 0in 5.4pt;height: 0.2in;vertical-align: bottom;"> <p style='margin:0in;font-size:15px;font-family:"Calibri",sans-serif;text-align:right;'><span style="color:black;">12</span></p> </td> </tr> </tbody> </table>

last_entry = 代码的最后一个匹配项的索引，从 0 开始。 prev_units = 上一次匹配的 cml_units，即列 cml_units 中的值，其中索引等于 last_entry 中的值 cml_units = 仅是数量列 + prev_units 列的总和

这是我获取所有先前匹配项索引的代码：

for t in (set(trans_df['ticker'])):
print (np.insert(trans_df[trans_df['ticker']==t].index.values.astype(np.float32),0,np.nan)[:-1])

如果不需要 last_entry 列，我们可以跳过该列，前提是还有另一种方法可以获取当前行之前的聚合数量。

Answer 1

我的朋友大卫向我展示了如何轻松地为单个自动收报机做到这一点：

trans_df.loc[trans_df['ticker'] == 'MMM', 'cml_units']= trans_df.loc[trans_df['ticker'] == 'MMM', 'quantity'].cumsum()

然后我可以使用 groupby 扩展它：

trans_df['cml_units']=trans_df.groupby('ticker')['quantity'].cumsum()

上面的代码有帮助，但我认为我可能仍然需要获取之前的代码匹配的索引，因为我还需要跟踪之前的平均成本。 当我出售股票时，我需要减去平均成本乘以已售股票数量的乘积，以确定出售的收益/损失并正确调整 cml_cost 的 cumsum。