Python—读取、写入和附加到文件

我是python新手。文件中有不同的端口号。我想遍历端口号。端口之间用逗号分隔。最后，我想把我的端口号附加到这个文件中。我写的代码不起作用，因为结尾总是有换行符。我怎样才能解决这个问题。还有更好的解决办法吗。这是我的密码-

        f = open("ports.txt", "r")
        line = f.readline()
        line = line.split(",")
        print(line)

        if len(line) > 0:
            del line[-1]
        for port in line:
            print(port)
        f = open("ports.txt", "a")
        m = str(self.myPort)+","
        f.write(m)
        f.close()

---

在处理逗号分隔的值时，通常应使用

下面的代码应该是不言自明的

import csv

# By using the with statement, you don't have to worry about closing the file
# for reading/writing. This is taken care of automaticly.
with open('ports.txt') as in_file:
    # Create a csv reader object from the file object. This will yield the
    # next row every time you call next(reader)
    reader = csv.reader(in_file)

    # Put the next(reader) statement inside a try ... except block. If the
    # exception StopIteratorion is raised, there is no data in the file, and
    # an IOError is raised.
    try:
        # Use list comprehension to convert all strings to integers. This 
        # will make sure no leading/trailing whitespace or any newline 
        # character is printed to the file
        ports = [int(port) for port in next(reader)]
    except StopIteration:
        raise IOError('No data in file!')

with open('ports.txt', 'wb') as out_file:
    # Create a csv writer object
    writer = csv.writer(out_file)
    # Append your port to the list of ports...
    ports.append(self.myPort)
    # ...and write the data to the csv file
    writer.writerow(ports)

---

在处理逗号分隔的值时，通常应使用

下面的代码应该是不言自明的

import csv

# By using the with statement, you don't have to worry about closing the file
# for reading/writing. This is taken care of automaticly.
with open('ports.txt') as in_file:
    # Create a csv reader object from the file object. This will yield the
    # next row every time you call next(reader)
    reader = csv.reader(in_file)

    # Put the next(reader) statement inside a try ... except block. If the
    # exception StopIteratorion is raised, there is no data in the file, and
    # an IOError is raised.
    try:
        # Use list comprehension to convert all strings to integers. This 
        # will make sure no leading/trailing whitespace or any newline 
        # character is printed to the file
        ports = [int(port) for port in next(reader)]
    except StopIteration:
        raise IOError('No data in file!')

with open('ports.txt', 'wb') as out_file:
    # Create a csv writer object
    writer = csv.writer(out_file)
    # Append your port to the list of ports...
    ports.append(self.myPort)
    # ...and write the data to the csv file
    writer.writerow(ports)

---

在处理逗号分隔的值时，通常应使用

下面的代码应该是不言自明的

import csv

# By using the with statement, you don't have to worry about closing the file
# for reading/writing. This is taken care of automaticly.
with open('ports.txt') as in_file:
    # Create a csv reader object from the file object. This will yield the
    # next row every time you call next(reader)
    reader = csv.reader(in_file)

    # Put the next(reader) statement inside a try ... except block. If the
    # exception StopIteratorion is raised, there is no data in the file, and
    # an IOError is raised.
    try:
        # Use list comprehension to convert all strings to integers. This 
        # will make sure no leading/trailing whitespace or any newline 
        # character is printed to the file
        ports = [int(port) for port in next(reader)]
    except StopIteration:
        raise IOError('No data in file!')

with open('ports.txt', 'wb') as out_file:
    # Create a csv writer object
    writer = csv.writer(out_file)
    # Append your port to the list of ports...
    ports.append(self.myPort)
    # ...and write the data to the csv file
    writer.writerow(ports)

---

在处理逗号分隔的值时，通常应使用

下面的代码应该是不言自明的

import csv

# By using the with statement, you don't have to worry about closing the file
# for reading/writing. This is taken care of automaticly.
with open('ports.txt') as in_file:
    # Create a csv reader object from the file object. This will yield the
    # next row every time you call next(reader)
    reader = csv.reader(in_file)

    # Put the next(reader) statement inside a try ... except block. If the
    # exception StopIteratorion is raised, there is no data in the file, and
    # an IOError is raised.
    try:
        # Use list comprehension to convert all strings to integers. This 
        # will make sure no leading/trailing whitespace or any newline 
        # character is printed to the file
        ports = [int(port) for port in next(reader)]
    except StopIteration:
        raise IOError('No data in file!')

with open('ports.txt', 'wb') as out_file:
    # Create a csv writer object
    writer = csv.writer(out_file)
    # Append your port to the list of ports...
    ports.append(self.myPort)
    # ...and write the data to the csv file
    writer.writerow(ports)

---

谢谢你的慷慨评论。我很抱歉问这个问题，但是“ports=[int（I）for line in inf for I in line.split（'，'）]”是什么意思？@eddard.stark：对于ports.txt文件中的每一行，它会将逗号分隔的数字拆分出来，并将每一行转换为整数。然后返回列表中的所有值。最好使用csv模块的方法提取值，而不是重新设计轮子。谢谢您的慷慨评论。我很抱歉问这个问题，但是“ports=[int（I）for line in inf for I in line.split（'，'）]”是什么意思？@eddard.stark：对于ports.txt文件中的每一行，它会将逗号分隔的数字拆分出来，并将每一行转换为整数。然后返回列表中的所有值。最好使用csv模块的方法提取值，而不是重新设计轮子。谢谢您的慷慨评论。我很抱歉问这个问题，但是“ports=[int（I）for line in inf for I in line.split（'，'）]”是什么意思？@eddard.stark：对于ports.txt文件中的每一行，它会将逗号分隔的数字拆分出来，并将每一行转换为整数。然后返回列表中的所有值。最好使用csv模块的方法提取值，而不是重新设计轮子。谢谢您的慷慨评论。我很抱歉问这个问题，但是“ports=[int（I）for line in inf for I in line.split（'，'）]”是什么意思？@eddard.stark：对于ports.txt文件中的每一行，它会将逗号分隔的数字拆分出来，并将每一行转换为整数。然后返回列表中的所有值。最好使用csv模块的方法提取值，而不是重新发明轮子