通过输入向字典添加新值

Question

我有以下代码，如果满足某些条件，我想在其中添加新值并向字典添加新行。然后在 text_widget 中打印字典。

def add_preprocessing_operation():
            # Clear the text_widget4 before updating
            text_widget4.delete('1.0', tk.END)

            # Get the inputs from the user
            sr_num_operation = int(input1.get())
            column_name = input2.get()

            # Call the check_preprocessing_operation() function
            preprocessing_dict = {}
            try:
                check_preprocessing_operation(df, sr_num_operation, column_name, preprocessing_dict)
            except ValueError as e:
                # Show a pop-up message if there is an error
                messagebox.showerror("Error", e)
                return

            # If there are any preprocessing operations in the dictionary, print them to text_widget4
            if preprocessing_dict:
                table = tabulate(preprocessing_dict.items(), headers=["Column Name", "Data-Preprocessing Operation"], tablefmt="grid", numalign="center", stralign="center")
                text_widget4.insert(tk.END, table)

            # If there are more than one row, add a newline character
            if table.count('\n') > 1:
                text_widget4.insert(tk.END, '\n')
                    
        def check_preprocessing_operation(df, sr_num_operation, column_name, preprocessing_dict):
            if sr_num_operation not in range(1, 10) or column_name not in df.columns:
                if sr_num_operation not in range(1, 10):
                    print("Invalid operation entered. Check list for reference!")
                if column_name not in df.columns:
                    print("Column ", column_name, " does not exist in the DataFrame.")
                return

            preprocessing_operation = preprocessing_operations[sr_num_operation]

            if len(preprocessing_dict) >= 10:
                raise ValueError("Maximum number of preprocessing operations reached. Cannot add more operations.")

            if preprocessing_operation == "Remove Rows with Null Values":
                if df[column_name].isnull().values.any():
                    messagebox.showerror("Error", "Operation cannot be applied to column. Column does not contains null values.")
                    return
                else:
                    preprocessing_dict.setdefault(column_name, []).append(preprocessing_operation)

            elif preprocessing_operation in ["Replace Null Values by Mean", "Replace Null Values by Median", "Replace Null Values by Mode"]:
                if df[column_name].dtype.kind not in 'fi':
                    messagebox.showerror("Error", "Operation cannot be applied to column. Column does not contain numeric data.")
                    return
                else:
                    preprocessing_dict.setdefault(column_name, []).append(preprocessing_operation)

            elif preprocessing_operation == "Perform One Hot Encoding":
                if df[column_name].dtype.kind not in 'O':
                    messagebox.showerror("Error", "Operation cannot be applied to column. Column does not contain categorical data.")
                    return
                else:
                    preprocessing_dict.setdefault(column_name, []).append(preprocessing_operation)

            elif preprocessing_operation == "Perform Label Encoding":
                if df[column_name].dtype.kind not in 'O':
                    messagebox.showerror("Error", "Operation cannot be applied to column. Column does not contain categorical data.")
                    return
                else:
                    preprocessing_dict.setdefault(column_name, []).append(preprocessing_operation)

            elif preprocessing_operation in ["Perform Min Max Scaling", "Perform Standardization", "Find Outliers and Remove the Rows with Outliers"]:
                if df[column_name].dtype.kind not in 'fi':
                    messagebox.showerror("Error", "Operation cannot be applied to column. Column does not contain numeric data.")
                    return
                else:
                    preprocessing_dict.setdefault(column_name, []).append(preprocessing_operation)

            else:
                print("Invalid operation entered.")

        
        add_button = tk.Button(inputs_frame, text="Add", width=10, command=add_preprocessing_operation)        
        add_button.grid(row=2, column=0, columnspan=2, pady=5)

但是这段代码似乎覆盖了字典，而不是在行中添加值！为了概览，截图贴在下面

Answer 1

正如一些评论指出的那样，您总是在 preprocessing_dict = {}

 中用 

add_preprocessing_operation 清空字典。你应该在函数外初始化它，也许作为 global 变量。