Python正则：仅转义双引号内字符的实现方法求助

Got it, let's work through this problem. The core challenge is targeting only the backslashes and double quotes that sit inside double-quoted segments of your string—leaving everything outside those quotes untouched. Here's a solid implementation using regular expressions and a callback function in Python 2.7:

Code Implementation #

import re

def escape_quoted_content(match):
    # Extract the content wrapped inside the double quotes
    inner_content = match.group(1)
    # First escape backslashes (critical to do this first!)
    escaped_backslashes = inner_content.replace('\\', '\\\\')
    # Then escape any double quotes inside the section
    escaped_quotes = escaped_backslashes.replace('"', '\\"')
    # Re-wrap the processed content in double quotes
    return '"{}"'.format(escaped_quotes)

# Your original string (Python 2.7 representation)
original = 'NotEscaped"S\\tr"ing"'
# Process the string with regex substitution
processed = re.sub(r'"([^"\\]*(?:\\.[^"\\]*)*)"', escape_quoted_content, original)

# Check the result using repr() to see the escaped format
print(repr(processed))
# Output: 'NotEscaped"S\\\\tr\\"ing"'

Breakdown of the Regex #

The pattern r'"([^"\\]*(?:\\.[^"\\]*)*)"' is designed to reliably match double-quoted sections even if they already contain escaped characters:

• ": Matches the opening double quote.
• ([^"\\]*(?:\\.[^"\\]*)*): The capturing group that grabs the content inside the quotes:
  • [^"\\]*: Matches any character that isn't a double quote or backslash (zero or more times).
  • (?:\\.[^"\\]*)*: A non-capturing group that handles escaped characters: it matches a backslash followed by any character, then more non-quote/non-backslash characters—repeating as needed. This ensures we don't break existing escaped content.
• ": Matches the closing double quote.

Why the Callback Order Matters #

We first escape backslashes, then double quotes. If we reversed this order, the backslash we added to escape a quote would itself get escaped, leading to incorrect results (like \\" becoming \\\\\" instead of just \\").

Verification #

For your example input 'NotEscaped"S\\tr"ing"', the code produces the exact output you wanted: 'NotEscaped"S\\\\tr\\"ing"'—the backslash in S\\tr becomes S\\\\tr, and the trailing quote inside the section becomes \\".

内容的提问来源于stack exchange，提问作者Gad82