python数据集-读取一组列并将其放置在单独的数据帧中？

有谁能帮助我，因为我是python新手。我有一个名为purchasing data的数据集，其中每个CaseID的每个PO活动的日志数据都存在于数据集中

Case Id     Activity                                 transactionstatus                                   
1           Create Purchase Requisition                     Closed
1           Create Request for Quotation Requester          Closed
1           Analyze Request for Quotation                   Closed
1           Send Request for Quotation to Supplier          Closed
1           Create Quotation comparison Map                 Closed
1           Analyze Quotation comparison Map                Closed
1           Choose best option                              Closed
1           Settle conditions with supplier                 Closed
1           Create Purchase Order                           Closed
1           Confirm Purchase Order                          Closed
1           Deliver Goods Services                          Closed
1           Release Purchase Order                          Closed
1           Approve Purchase Order for payment              Closed
1           Send invoice                                    Closed
1           Release Supplier's Invoice                      Closed
1           Authorize Supplier's Invoice payment            Closed
1           Pay invoice                                     Closed

在这里，每个案例Id都被视为一个变量，所以总共有1949个这样的变量

例如：案例Id:1被视为活动列“创建请购单”到“支付发票”的一个变量，然后交易状态被视为“已关闭”。（如上数据）

现在有很多caseID的transactionStatus为“open”，现在我要做的是尝试获取所有caseID和相应的活动（活动“create…”到“analyze…”的全部数据），该活动的transactionStatus为“open”，并尝试将其放在单独的数据集中

例如：

Case ID Activity                                         TransactionStatus
1941    Create Purchase Requisition                            Closed
1941    Analyze Purchase Requisition                           Closed
1941    Create Request for Quotation Requester Manager         Closed
1941    Analyze Request for Quotation                           Open
1949    Create Purchase Requisition                            Closed
1949    Analyze Purchase Requisition                            Open

总共有196条记录有公开交易状态！ 有人能帮我吗？我能用什么方法来做这件事

df = df[df.loc[:, 'caseID'].isin(df[df['TransactionStatus'] == 'Open']['caseID'])]

---

您需要将

Open

放在引号中。谢谢！这正是我所期待的结果！