Question

您好我在使用python修改文本行时遇到问题。我正在制作工资单应用程序，我无法使用修改方法。我不明白为什么我搜索的条目不会在新文件中删除。我将文件复制到临时文件，然后重命名临时文件，但旧条目保持不变。

def modEmp():
    empFile = open("employees.txt", 'r')
    empFile2= open("temp.txt",'w')
    line1 = empFile.readline().rstrip("\n")
    name = input("Enter in your employee name that you would like to modify\n")
    while line1 != '':
        line1 = line1.split(" ") #split line into list
        name = line1[0] + ' ' + line1[1]
        if name[0] == line1[0] and name[0] == line1[0]:
            print('Enter the modified entry:\n')
            list = [0] * 4
            list [0] = input('Enter first name:\n')
            list [1] = input('Enter last name:\n')
            list [2] = input('Enter pay rate:\n')
            list [3] = input('Enter hours worked:\n')
            empFile2.write(list[0] + ' ' + list[1] + ' ' + list[2] + ' ' + list[3] + "\n")

        else:
            empFile2.write(line1 + "\n")

        line1 = empFile.readline().rstrip("\n") 
    #Close file
    empFile.close()
    empFile2.close()
    os.remove('employees.txt')
    os.rename('temp.txt','employees.txt')

Answer 1

您的代码存在一些严重问题：

name = input("Enter in your employee name that you would like to modify\n")
...
    name = line1[0] + ' ' + line1[1]

在查看前会覆盖name，所以无论输入什么都不重要。

正如Hugh Bothwell所指出的那样：

line1 = line1.split(" ") #split line into list
    name = line1[0] + ' ' + line1[1]
    if name[0] == line1[0] and name[0] == line1[0]:

尝试将字符串与同一字符串中的第一个字符进行比较，如果name是单个字符，则仅为True。

相反，你想做这样的事情：我通过使用with清理了很多额外的烦恼，处理为我们关闭文件并让内置{{1} } loop：

我还将您的列表变量重命名为for element in list:，因为覆盖内置lst变量会导致错误。

list

请注意，如果您有多个＆＃34;账单＆＃34;并且您搜索＆＃34; bill＆＃34;，系统将提示您更改它们。此外，此功能没有中止，并且具有破坏性，因此您将丢失为这些员工存储的任何信息。在真正的工资单应用程序中，这可能是灾难性的。

此外，如果您想让它更具可重用性，而不是在列表中指定四个元素，您可以：

def modEmp():
    with open("employees.txt", 'r') as empFile, open("temp.txt", "w") as empFile2:
        name = input("Enter in your employee name that you would like to modify\n")
        for line in empFile:
            if name in line:
                print('Enter the modified entry:\n')
                lst = []
                lst.append(input('Enter first name:\n'))
                lst.append(input('Enter last name:\n'))
                lst.append(input('Enter pay rate:\n'))
                lst.append(input('Enter hours worked:\n'))
                empFile2.write("{} {} {} {}\n".format(*lst))
            else:
                empFile2.write(line)

    # I highly encourage making a backup, as sooner or later
    # someone will mess it up
    os.rename('employees.txt', 'employees.bkp')
    os.rename('temp.txt','employees.txt')

这将编辑与提示一样多的输入，然后将它们作为一行分隔在文件中，尽管它不那么明显你正在做什么。

Answer 2

正如评论中所提到的，您的代码存在一些问题......

在您的情况下使用with open(name) as f:语法是good practice。

以下是我认为可以解决您问题的解决方案。

def modify():
    with open("employees.txt", 'r+') as employee_file:  # Opening file in read and write mode
        temp = employee_file.readlines()  # Get all lines
        employee_file.seek(0)  # Reset position in file

        name = input("Enter in your employee name that you would like to "
                     "modify\n")

        first, last = name.split(' ')  # Assuming this is what you intended

        for line in temp:
            # There's no reason to use a list here, and avoid using object names as variables
            if first in line and last in line:
                print('Enter the modified entry:\n')
                first_name = input('Enter first name:\n')
                last_name = input('Enter last name:\n')
                pay_rate = input('Enter pay rate:\n')
                hours = input('Enter hours worked:\n')

                line_to_write = ' '.join([first_name, last_name,
                                          pay_rate, hours])
                employee_file.write(line_to_write + "\n")
            else:
                employee_file.write(line + "\n")

        employee_file.truncate()

需要帮助使用python修改文本文件中的行

2 个答案: