Question

给出一个简单的功能：

def A(a = 1, b = 2):
    return a+b

我想编写另一个函数来更改a或b的默认参数值。用户可以通过设置var = a或var = b来指定要更改的参数。例如：

def B(var = 'a', new_value = 10):
    temp_dict = {var:new_value}
    ans = A(var)
    return ans

或

def B(var = 'a', new_value = 10):
    ans = A(var = new_value)
    return ans

在功能def B()中，设置var = a和var = new_value = 10后，我希望A(var = new_value)达到与A(a = 10)相同的效果。你知道写函数def B()的正确方法吗？谢谢。

Answer 1

你快到了。在6395ms函数中，在调用B()时，您需要解压缩A()并将其作为参数传递给temp_dict。见下文：

A()

有关此>>> def A(a = 1, b = 2): ... return a+b ... >>> def B(var = 'a', new_value = 10): ... temp_dict = {var:new_value} ... ans = A(**temp_dict) # ^ unpack the dict, and pass it as an argument ... return ans ... >>> B() 12如何与词典一起使用的详细信息，请查看：

Python: *args and **kwargs?

What does ** (double star/asterisk) and * (star/asterisk) do for parameters?

Answer 2

我冒昧地解释了OP所说的他想要的东西，即更改默认参数值，a或b 。所以我做的是返回一个转换后的函数A，其中a或b默认值通过partial：

更改

func tableView(_ tableView: UITableView, trailingSwipeActionsConfigurationForRowAt indexPath: IndexPath) -> UISwipeActionsConfiguration? {
    let delete = UIContextualAction(style: .normal, title: "Delete") { action, view, completionHandler in
      print("Deleting!")
      completionHandler(false)
    }
    delete.backgroundColor = UIColor.red
    let config = UISwipeActionsConfiguration(actions: [delete])
    config.performsFirstActionWithFullSwipe = false
    return config
  }

样本输出：

 *** Assertion failure in -[UISwipeActionController swipeHandlerDidBeginSwipe:], /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit_Sim/UIKit-3694.4.18/SwipeActions/UISwipeActionController.m:268
 *** Terminating app due to uncaught exception 'NSInternalInconsistencyException', reason: 'No occurrence for index path (null)'

这与请求的后半部分有所不同，即基于$sql2 = "SELECT trans_details.*, company.comp_name FROM trans_details INNER JOIN company ON trans_details.comp_id=company.comp_id WHERE trans_details.comp_id = '$company' and trans_date BETWEEN CAST('$startdate' as date) and CAST('$enddate' as date)"; $stmt2 = sqlsrv_query($conn, $sql2); if($stmt2 ===FALSE){ die(print_r(sqlsrv_errors(), TRUE)); }else{ echo "<center><h3>CANTEEN TRANSACTION LISTING<br>Summary By Company</h3> <strong>Date From : </strong>".$datestart."  <strong>To : </strong>".$dateend."<br>"; ?> <center><table border="1" cellpadding="4px"> <thead> <tr> <th>Cashier#</th> <th>Total Txn</th> <th>Total Amount (RM)</th> <th>Total Cash (RM)</th> <th>Total Subsidy (RM)</th> </tr> </thead> <tbody> <?php //count transaction $compname2 = "SELECT * from company where comp_id='$company'"; $compp = sqlsrv_query($conn, $compname2); while ($c =sqlsrv_fetch_array($compp, SQLSRV_FETCH_ASSOC)) { echo "<center><strong> Company :</strong>".$c['comp_name']."</center><br><br>"; } $txnT = 0; $sumAmount = 0; $sumCash = 0; $sumSubsidy = 0; $txn = "SELECT user_id,count(1) as txnT,sum(CAST(amount AS DECIMAL(12,2))) as sumAmount, sum(CAST(cash AS DECIMAL(12,2))) as sumCash,sum(CAST(subsidy AS DECIMAL(12,2))) as sumSubsidy from trans_details where trans_date BETWEEN CAST('$startdate' as date) and CAST('$enddate' as date) group by user_id"; $res = sqlsrv_query($conn, $txn); //count end while($row2 = sqlsrv_fetch_array($stmt2, SQLSRV_FETCH_ASSOC)) //fetching main query { while($num = sqlsrv_fetch_array($res, SQLSRV_FETCH_ASSOC)) //fetching 1st condition { echo "<center><tr><td>".$num['user_id']."</td>" . "<td align='right'>".$num['txnT']."</td>" . "<td align='right'>".$num['sumAmount']."</td>" . "<td align='right'>".$num['sumCash']."</td>" . "<td align='right'>".$num['sumSubsidy']."</td>" . "</tr>"; } } } //sum up all $ttl = "SELECT count(1) as Txn,sum(CAST(amount as DECIMAL(12,2))) as ttlamount, sum(CAST(cash AS DECIMAL(12,2))) as ttlcash,sum(CAST(subsidy AS DECIMAL(12,2))) as ttlsubsidy from trans_details where trans_date BETWEEN CAST('$startdate' as date) and CAST('$enddate' as date)"; $re = sqlsrv_query($conn, $ttl); while($num_row = sqlsrv_fetch_array($re, SQLSRV_FETCH_ASSOC)) //fetching 2nd condition { echo "<tr> <td><strong>SUB TOTALS</strong></td>" ."<td align='right'><strong>".$num_row['Txn']."</strong></td>" ."<td align='right'><strong>".$num_row['ttlamount']."</strong></td>" ."<td align='right'><strong>".$num_row['ttlcash']."</strong></td>" ."<td align='right'><strong>".$num_row['ttlsubsidy']."</strong></td>" ."</tr></tbody></center>"; }的某些内容作为函数签名。

唯一的问题是，如果你不使用关键字参数，它就会很开心：

while($num = sqlsrv_fetch_array($res, SQLSRV_FETCH_ASSOC))

将函数参数名称传递给Python中的另一个函数

2 个答案: