Python GUI读取文件遇FileNotFoundError，求文件读取与数值相减解决方案

编写了一段Python GUI代码，目标是让用户选择三个不同文件，读取内容后进行数值相减操作。但点击执行按钮时出现FileNotFoundError，报错信息如下：

return self.func(*args)
    with open('CHGCAR1', 'r') as f:
FileNotFoundError: [Errno 2] No such file or directory: 'CHGCAR1'

涉及的charge_density函数代码：

def charge_density():
     with open('CHGCAR1', 'r') as f:
            CHGCAR1 = f.read()
            CHGCAR1_ints = [safeFloat(x) for x in CHGCAR1.split()]
            print(CHGCAR1_ints)
            CHGCAR1_ints_1 = [c for c in CHGCAR1_ints if c is not None]
            print(CHGCAR1_ints_1)
     with open('CHGCAR2', 'r') as f:
            CHGCAR2 = f.read()
            CHGCAR2_ints = [safeFloat(x) for x in CHGCAR2.split()]
            print(CHGCAR2_ints)
            CHGCAR2_ints_2 = [c for c in CHGCAR2_ints if c is not None]
            print(CHGCAR2_ints_2)
     with open('CHGCAR3', 'r') as f:
            CHGCAR3 = f.read()
            CHGCAR3_ints = [safeFloat(x) for x in CHGCAR3.split()]
            print(CHGCAR3_ints)
            CHGCAR3_ints_3 = [c for c in CHGCAR3_ints if c is not None]
            print(CHGCAR3_ints_3)
     
     with open("CHGCAR_final.txt", 'w') as f:
            for i in range( min( len(CHGCAR1_ints_1), len(CHGCAR2_ints_2), len(CHGCAR3_ints_3)) ) :
             f.write(str(CHGCAR1_ints_1[i] - CHGCAR2_ints_2[i] - CHGCAR3_ints_3[i]))
            f.write(' ')
            print(f)

问题根源 #

代码硬编码了CHGCAR1、CHGCAR2、CHGCAR3固定文件名，但GUI中用户选择的文件路径并未传递到charge_density函数，导致程序在当前工作目录中查找不存在的固定名称文件，触发报错。

具体调整步骤 #

1. 修改函数参数，接收用户选择的文件路径
   让charge_density函数通过参数获取实际文件路径，而非依赖固定文件名。
2. 完善GUI文件选择逻辑
   在GUI中添加文件选择功能，保存用户选中的三个文件路径，点击计算按钮时传递给函数。
3. 优化代码结构与逻辑
   封装重复的文件读取逻辑，修复原代码中输出文件的缩进错误（原代码仅在循环结束后写入一个空格）。

调整后的示例代码 #

import tkinter as tk
from tkinter import filedialog, messagebox

# 存储用户选择的三个文件路径
selected_files = []

def select_three_files():
    global selected_files
    # 弹出文件选择框，允许选择多个文件
    selected_files = filedialog.askopenfilenames(
        title="选择三个CHGCAR文件",
        filetypes=[("文本文件", "*.txt"), ("所有文件", "*.*")]
    )
    # 校验选择的文件数量
    if len(selected_files) != 3:
        messagebox.showwarning("提示", "请选择恰好三个文件！")
        selected_files = []

def safeFloat(x):
    try:
        return float(x)
    except ValueError:
        return None

def read_and_parse_file(file_path):
    """封装文件读取与数值解析逻辑"""
    with open(file_path, 'r', encoding='utf-8') as f:
        content = f.read()
    # 转换为数值列表并过滤无效值
    num_list = [safeFloat(item) for item in content.split()]
    return [num for num in num_list if num is not None]

def charge_density(file1, file2, file3):
    # 读取并解析三个文件
    list1 = read_and_parse_file(file1)
    list2 = read_and_parse_file(file2)
    list3 = read_and_parse_file(file3)
    
    # 取最小长度避免索引越界
    min_length = min(len(list1), len(list2), len(list3))
    
    # 写入计算结果
    with open("CHGCAR_final.txt", 'w', encoding='utf-8') as f:
        for i in range(min_length):
            result = list1[i] - list2[i] - list3[i]
            f.write(f"{result} ")
    print("计算完成，结果已保存至CHGCAR_final.txt")

# 构建GUI界面
root = tk.Tk()
root.title("电荷密度计算工具")

# 文件选择按钮
select_btn = tk.Button(root, text="选择三个文件", command=select_three_files)
select_btn.pack(pady=15)

# 计算按钮
calc_btn = tk.Button(
    root, 
    text="执行数值相减", 
    command=lambda: charge_density(*selected_files) if len(selected_files)==3 else messagebox.showwarning("提示", "请先选择三个文件！")
)
calc_btn.pack(pady=15)

root.mainloop()

关键说明 #

• 函数charge_density通过参数接收用户选择的实际文件路径，彻底解决文件找不到的问题。
• 新增read_and_parse_file辅助函数，复用文件读取与数值转换逻辑，简化代码结构。
• 修复原代码中f.write(' ')的缩进错误，确保每个计算结果后都添加空格。
• 添加文件数量校验，避免用户未选够文件时执行计算。

内容的提问来源于stack exchange，提问作者msut akdss