令牌捕获序列python无法正常工作 [英] token capture sequences python not working correctly

问题描述

我正在测试我的 python grpper 脚本.它需要多种搜索模式，并且适用于正则表达式和纯文本.

I am testing out my python grepper script. It takes multiple search patterns, and works well with regular expressions and plain text.

对于这个测试，我的 input.txt 有以下两行:

For this test, my input.txt has the following two lines:

foo blah is a bar
foo blah is bar

如果我跑:

cat input.txt | ./pgreper.py "foo %{0} is a %{1}"

我应该得到:foo blah 是一个 bar，作为输出，但是我什么也没得到.

I should get: foo blah is a bar, as output, however I get nothing.

在这方面的任何帮助将不胜感激.

Any help in this area would be greatly appreciated.

谢谢:)

ps 请忽略我的评论.

ps please ignore my comments.

#!/usr/bin/python3

import sys
import re
import time
import datetime
import inspect
import argparse

# The following section allows arguments to be passed to the module, eg input | ./pgreper.py pattern pattern --debug
parser = argparse.ArgumentParser(description='Python Grep.')
# Enable debugging, by adding --debug at the end of command
parser.add_argument('--debug', action='store_true', help='Print debug messages')
# nargs='+', enables multiple patterns to be entered at the commandline eg input | ./pgreper.py pattern pattern
parser.add_argument('pattern', type=str, nargs='+', help='Pattern(s) for pgrepping')
args = parser.parse_args()


# This is the class that allows for debugging a line in sys.stdin, if it matches all patterns.
class CodeTrace(object):
    def __init__(self, line, pattern):
        self.line = line
        self.pattern = pattern

    # @staticmethod
    # This is the degugging method
    def trace(self, line, pattern):
        # Capture the current time, and format the timestamp, into a readable format
        ts = datetime.datetime.fromtimestamp(time.time()).strftime('[%Y-%m-%d %H:%M:%S:%f]')
        # Inspect allows us to blah, inspecting the stack allows us to retrieve information
        stack = inspect.stack()
        # Retrieve calling class information
        the_class = stack[1][0].f_locals["self"].__class__
        # Retrieves the calling method information
        the_method = stack[1][0].f_code.co_name
        # Retrieves the calling method's variables
        the_variables = stack[1][0].f_code.co_varnames
        # Formats the contents of the debug trace into a readable format,
        # Any parameters passed to the method and the return value, are included in the debug trace
        debug_trace = ("{} {}.{}.{} {} {} ".format(ts, str(the_class), the_method,the_variables, pattern, line))
        # Send out the debug trace as a standard error output
        sys.stderr.write(debug_trace + "\n")


# This is the class that does the pattern matching
class Grepper(object):
    def __init__(self, patterns, debug=False):
        # Every pattern that this module takes is compiled here, so that it may be searched for in sys.stdin
        self.patterns = [re.compile(p) for p in patterns]
        self.debug = debug

    # This method compares the input, to the patterns compiled in Grepper
    def matchline(self, debug):
        for line in sys.stdin:
            # This line compares all the patterns to the input, only if the input matches ALL patterns does it pass
            if all(p.search(line) for p in self.patterns):
                sys.stdout.write(line)
                # this if statement runs the CodeTrace.trace function, if the user adds the --debug option in the cli
                if self.debug:
                    CodeTrace(line, self.patterns).trace(line, args.pattern)


# This main function calls the grepper class and the matchline method, for the purpose of pattern matching
def main():
    print(args.pattern)
    Grepper(args.pattern, args.debug).matchline(args.debug)

# This allows the module to be used as a standalone module, or a reusable module in a different program
if __name__ == "__main__":
    main()

推荐答案

您当前将命令行参数解释为正则表达式模式，而不替换占位符 %{0} 和 %{1}.您可能想用 .* 或类似的东西替换占位符，如下所示:

You are currently interpreting the command line arguments as regex patterns, without replacing the placeholders %{0} and %{1}. You'll probably want to replace the placeholders with .* or something similar, like so:

class Grepper(object):
    def __init__(self, patterns, debug=False):
        patterns= [re.sub(r'%\{\d\}', '.*', p) for p in patterns]
        self.patterns = [re.compile(p) for p in patterns]

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