Python从文件中删除行块

我正在努力弄清楚应该如何从文件中删除一段行。下面是代码

#!/usr/bin/python
import argparse
import re
import string

##getting user inputs
p = argparse.ArgumentParser()
p.add_argument("input", help="input the data in format ip:port:name", nargs='*')  
args = p.parse_args()
kkk_list = args.input


def printInFormat(ip, port, name):
    formattedText = '''HOST Address:{ip}:PORT:{port} 
                        mode tcp 
                        bind {ip}:{port} name {name}'''.format(ip=ip, 
                                                                port=port, 
                                                                name=name)
    textWithoutExtraWhitespaces =  '\n'.join([line.strip() for line in formattedText.splitlines()])
    # you can break above thing
    # text = ""
    # for line in formattedText.splitlines():
    #       text += line.strip()
    #       text += "\n" 

    return(formattedText)

#####here im writing writing the user inoput to a file and it works great.
#with open("file.txt", "a") as myfile:
#    for kkk in kkk_list:
#         ip, port, name = re.split(":|,", kkk)
#         myfile.write(printInFormat(ip, port, name))

###### here is where im struggling. 
for kkk in kkk_list:
    ip, port, name = re.split(":|,", kkk)
    tobedel = printInFormat(ip, port, name)  
    f = open("file.txt", "r+")
    d = f.readlines()
    f.seek(0)
    if kkk != "tobedel":
        f.write(YY)
f.truncate()
f.close()

如您所见，我在file.txt中添加了用户输入。i、 e（格式：ip:端口：名称）。当脚本作为./script.py 192.168.0.10:80:string 192.168.0.10:80:string执行时，文件将包含以下条目

Host Address:192.168.0.10:PORT:80
mode tcp
bind 192.168.0.10:80 abc    
Host Address:10.1.1.10:PORT:443
mode tcp
bind 10.1.1.10:443 xyz

---

现在，我想在以相同的方式提供用户输入时删除file.txt中的行。运行上述代码时，不会发生任何事情。我是个初学者，如果你能帮我理解，我真的很感激。这个问题与

有多种方法。我试图创建一个新文件，留下所有的块。您可以删除旧文件并将新文件重命名为旧文件。 以下是相同的工作代码

 #!/usr/bin/python
 import argparse
 import re
 import string

##getting user inputs
p = argparse.ArgumentParser()
p.add_argument("input", help="input the data in format ip:port:name", nargs='*')  
args = p.parse_args()
kkk_list = args.input # ['192.168.1.10:80:name1', '172.25.16.2:100:name3']



# returns the next block from the available file. Every block contains 3 lines as per definition.
def getNextBlock(lines, blockIndex):
    if len(lines) >= ((blockIndex+1)*3):
        line = lines[blockIndex*3]
        line += lines[blockIndex*3+1]
        line += lines[blockIndex*3+2]
    else:
        line = ''

    return line

# file  - holds reference to existing file of all blocks. For efficiency keep the entire content in memory (lines variable)
file = open("file.txt", "r")
lines = file.readlines()
linesCount = len(lines)

# newFile holds reference to newly created file and it will have the resultant blocks after filtering
newFile = open("file_temp.txt","w")


# loop through all inputs and create a dictionary of all blocks to delete. This is done to have efficiency while removing the blocks with O(n) time

delDict = {}
for kkk in kkk_list:
    ip, port, name = re.split(":|,", kkk)
    tobedel = printInFormat(ip, port, name)
    delDict[tobedel] = 1

for i in range(linesCount / 3):
    block = getNextBlock(lines, i)
    if block in delDict:
        print 'Deleting ... '+block
    else:
        #write into new file
        newFile.write(block)

file.close()
newFile.close()

#You can drop the old file and rename the new file as old file

---

希望有帮助

让我指出你缺少的一些小东西

for kkk in kkk_list:
    ip, port, name = re.split(":|,", kkk)
    tobedel = printInFormat(ip, port, name)  
    f = open("file.txt", "r+")
    d = f.readlines()
    f.seek(0)
    if kkk != "tobedel":
        f.write(YY)
f.truncate()
f.close()

您在循环内部打开了文件，在外部关闭了文件。文件对象超出范围。将

与

一起使用，它会自动为您处理上下文

在循环中打开一个文件是一个坏主意，因为它将创建太多的文件描述符，这将消耗大量资源

你在写作的时候从来没有提到过什么是

YY

当您试图一次性删除多行时，可以在此处删除行，因此

d=f.readlines（）

应该是

d=f.read（）

下面是更新后的代码

#!/usr/bin/python
import argparse
import re
import string

p = argparse.ArgumentParser()
p.add_argument("input", help="input the data in format ip:port:name", nargs='*')  
args = p.parse_args()
kkk_list = args.input # ['192.168.1.10:80:name1', '172.25.16.2:100:name3']


def getStringInFormat(ip, port, name):
    formattedText = "HOST Address:{ip}:PORT:{port}\n"\
                    "mode tcp\n"\
                    "bind {ip}:{port} name {name}\n\n".format(ip=ip, 
                                                                port=port, 
                                                                name=name)

    return formattedText

# Writing the content in the file
# with open("file.txt", "a") as myfile:
#    for kkk in kkk_list:
#         ip, port, name = re.split(":|,", kkk)
#         myfile.write(getStringInFormat(ip, port, name))



with open("file.txt", "r+") as f:
    fileContent = f.read()

    # below two lines delete old content of file
    f.seek(0)
    f.truncate()

    # get the string you want to delete
    # and update the content
    for kkk in kkk_list:
        ip, port, name = re.split(":|,", kkk)

        # get the string which needs to be deleted from the file
        stringNeedsToBeDeleted = getStringInFormat(ip, port, name)

        # remove this from the file content    
        fileContent = fileContent.replace(stringNeedsToBeDeleted, "")

    # delete the old content and write back with updated one
    # f.truncate(0)
    f.write(fileContent)

# Before running the script file.txt contains 

# HOST Address:192.168.1.10:PORT:80
# mode tcp
# bind 192.168.1.10:80 name name1
#
# HOST Address:172.25.16.2:PORT:100
# mode tcp
# bind 172.25.16.2:100 name name3

# After running file.txt will be empty
# as we have deleted both the entries.

---

你想删除什么？你能解释一下吗。可能是同一个例子。您的代码并不清楚。@ArunKumar我正试图删除第二个代码窗口中提到的2个块。当脚本使用args:：运行时，它应该从file.txt中删除相应的条目。谢谢，非常感谢。你能帮我再检查一遍代码吗？因为当脚本以“/del.py 192.168.0.10:80:somename1”的形式运行时，它不会从文件中删除3行或任何内容。我有几行主机地址：192.168.0.10:PORT:80/mode tcp/bind 192.168.0.10:80 somename1。请注意“/”对应一个新行，因为此窗口不允许我使用enter键。请帮助rahul，我想我们已经非常接近了。@bindo使用上面的代码，它会工作的。前面的代码有一些空格和制表符，我在上面的代码中修复了它。我又检查了一遍。非常感谢拉胡尔，你真是个天才。我刚刚试过代码，它工作得很好。解决这个问题的方法非常好，在变量中指定了所有行，而不是强调复杂的正则表达式模式。我稍微修改了一下代码，搜索和删除带有标签的行，到目前为止没有问题。谢谢。正则表达式会更好，但您可以稍后再尝试。另外，如果你喜欢这个答案，请把它投上去。非常感谢。如果您不介意的话，请将def getNextBlock的评论包括在内？我的主要目标是学习，这将非常有帮助。现在更有意义了。谢谢。我会再测试一次