Question

可能重复：
Python 3 regular expression to find multiline comment

我需要一些关于如何做到这一点的投入，非常感谢您的投入，我查看了其他帖子，但没有一个符合我的要求。

How to remove line from the file in python Remove lines from textfile with python

我需要根据提供的输入字符串匹配文件中的多行注释。

实施例： -

让我们说如果文件“test.txt”有以下注释，如果inputstring =“这是一个测试，脚本编写”这个注释需要从文件中删除

import os
import sys

import re
import fnmatch

def find_and_remove(haystack, needle):
    pattern = re.compile(r'/\*.*?'+ needle + '.*?\*/', re.DOTALL)
    return re.sub(pattern, "", haystack)

for path,dirs,files in os.walk(sys.argv[1]):
    for fname in files:
        for pat in ['*.cpp','*.c','*.h','*.txt']:
            if fnmatch.fnmatch(fname,pat):
                fullname = os.path.join(path,fname)
                with open(fullname, "r") as f:
                    find_and_remove(f, r"This is a test, script written")

错误： -

Traceback (most recent call last):
  File "comment.py", line 16, in <module>
    find_and_remove(f, r"This is a test, script written")
  File "comment.py", line 8, in find_and_remove
    return re.sub(pattern, "", haystack)
  File "/usr/lib/python2.6/re.py", line 151, in sub
    return _compile(pattern, 0).sub(repl, string, count)
TypeError: expected string or buffer

Answer 1

当我看到这个问题时，首先想到的是“状态机”，每当我想到python中的“状态机”时，首先想到的是“生成器”a.k.a. yield：

def skip_comments(f):
    """
    Emit all the lines that are not part of a multi-line comment.
    """
    is_comment = False

    for line in f:
        if line.strip().startswith('/*'):
            is_comment = True

        if line.strip().endswith('*/'): 
            is_comment = False
        elif is_comment:
            pass
        else:
            yield line


def print_file(file_name):
    with file(file_name, 'r') as f:
        skipper = skip_comments(f)

        for line in skipper:
            print line,

编辑：user1927396通过指定它只是要排除的特定块（包含特定文本）来提高赌注。由于它在评论栏内，如果我们需要拒绝该块，我们将不会预先知道。

我的第一个想法是缓冲。确认。便便。我的第二个想法是令人难以忘怀的克制，我已经在脑子里扛了15年，从来没有使用到现在：“堆叠状态机”......

def squelch_comment(f, first_line, exclude_if):
    """
    Comment is a multi-line comment that we may want to suppress
    """
    comment = [first_line]

    if not first_line.strip().endswith('*/'):
        for line in f:

            if exclude_if in line:
                comment = None

            if comment and len(comment):
                comment.append(line)

            if line.strip().endswith('*/'):
                break

    if comment:
        for comment_line in comment:
            yield '...' + comment_line


def skip_comments(f):
    """
    Emit all the lines that are not part of a multi-line comment.
    """
    for line in f:
        if line.strip().startswith('/*'):
            # hand off to the nested, comment-handling, state machine
            for comment_line in squelch_comment(f, line, 'This is a test'):
                yield comment_line
        else:
            yield line


def print_file(file_name):
    with file(file_name, 'r') as f:
        for line in skip_comments(f):
            print line,

Answer 2

这应该适用于原则

def skip(file, lines):
 cline = 0
 result = ""
 for fileLine in file.read():
  if cline not in lines:
   result += fileLine
  cline += 1
 return result

行必须是数字列表，文件必须是打开的文件

Answer 3

这个在请求中执行：删除包含所需字符串的所有多行注释：

将其放在名为program.txt

的文件中

/*
 * This is a test, script written
 * This is a comment line
 * Multi-line comment
 * Last comment
 *
 */

some code

/*
 * This is a comment line
 * And should 
 *     not be removed
 *
 */

more code

然后搜索并替换。只需确保needle不会引入一些正则表达式特殊字符。

import re

def find_and_remove(haystack, needle):
    pattern = re.compile(r'/\*.*?'+ needle + '.*?\*/', re.DOTALL)
    return re.sub(pattern, "", haystack)

# assuming your program is in a file called program.txt
program = open("program.txt", "r").read()

print find_and_remove(program, r"This is a test, script written")

结果：

some code

/*
 * This is a comment line
 * And should 
 * not be removed
 *
 */

more code

它适应related question

中的正则表达式

编辑代码中的最后一部分：

for path,dirs,files in os.walk(sys.argv[1]):
    for fname in files:
        for pat in ['*.cpp','*.c','*.h','*.txt']:
            if fnmatch.fnmatch(fname,pat):
                fullname = os.path.join(path,fname)
                # put all the text into f and read and replace...
                f = open(fullname).read()
                result = find_and_remove(f, r"This is a test, script written")

                new_name = fullname + ".new"
                # After testing, then replace newname with fullname in the 
                # next line in order to replace the original file.
                handle = open(new_name, 'w')
                handle.write(result)
                handle.close()

确保在needle中转义所有正则表达式特殊字符，例如().如果您的文字包含括号，例如(any text)，则它们应显示在needle \(any text\)

中

使用python从文件中删除行

3 个答案: