Question

我正在关注Python for Data Analysis by Wes McKinney中的示例，并且遇到问题：一旦我合并了我创建的DataFrame，合并的DF显示为空DF，即使组件DF显示为填充。

代码是：

    while (rsLoadList.next()) {
    cols="REGNO,CustNo,ENTITYTYPE ";

    queryCmd = "SELECT  " + cols + "  FROM " + rsLoadList.getString("Tbl") + 

   " WHERE "+ likeFilter  + " ORDER BY "+ rsLoadList.getString("Desc");
    PrintDebug.println("cmd2: " + queryCmd);    
    rsQuery = aDbManager.retrieveRec(queryCmd);

    String regno = "";                                      
    while (rsQuery.next()) {                                            %>
    <script>
    $('#Customer_Number').val(<%=rsQuery.getString(1)%>);
    $('#ID_Number').val(<%=rsQuery.getString(2)%>);
    </script>
    PrintDebug.println("Customer_Number: " + rsQuery.getString(1));
     PrintDebug.println("ID_Number: " + rsQuery.getString(2));
    }
    }



 function refreshRecordCustNameList(rec,filter){  
    $.ajax({
        type: "POST",
        url: "LoadDropdownSubAccNo.jsp",
        data: "FieldFilter="+filter+"&Fieldname=" + rec + "&MappingID=<%=MappingID%>",
        success: function(data){


            $("input[id='Customer_Number']").html(''); 
        $("input[id='Customer_Number']").html(data);
                /*$("input[id='ID_Number']").html('');
             $("input[id='ID_Number']").html(data); */
        },
        error: function(msg){
            bootbox.alert({
                title:"Error"+  $("select[id='Customer_Number']").html(data),
                message: "Failed to load the list.",
            });
        }
        });
}

然后当我检查data = pd.merge(pd.merge(ratings, users), movies)时，它显示为空：

data

当我检查组件DF时，它们都包含数据：

Empty DataFrame
Columns: [user_id, rating, timestamp, gender, age, occupation, zip, movie_id, title, genres]
Index: []

为什么会发生这种情况，我该如何解决？

合并后在pandas中清空DataFrame

0 个答案: