使用Regex解析含值内逗号的逗号分隔键值对

Nice problem! Parsing this structured comma-separated list requires a regex that can handle different value types (single quoted strings, unquoted booleans/numerics, and arrays of those) without splitting on commas that are inside arrays or quotes. Here's a complete solution tailored to your needs:

Step 1: Split the Input into Individual Key-Value Pairs #

First, we need to split the input string into separate key-value pairs without breaking commas that are inside parentheses or single quotes. Use this regex to split on valid top-level commas:

,(?=(?:[^']*'[^']*')*[^']*$)(?=(?:[^()]*\([^()]*\))*[^()]*$)

How this works: #

• ,: Matches a comma
• (?=(?:[^']*'[^']*')*[^']*$): Positive lookahead ensuring the comma is outside any single quotes (counts pairs of quotes to confirm we're not inside one)
• (?=(?:[^()]*\([^()]*\))*[^()]*$): Another positive lookahead ensuring the comma is outside any parentheses (counts pairs of parentheses to avoid splitting inside arrays)

Step 2: Parse Each Key-Value Pair #

For each pair from the split, use this regex to extract the key and its corresponding value:

^(\w+)\s*=\s*((?:'[^']*')|(?:TRUE|FALSE|\d+)|(?:\((?:(?:'[^']*')|(?:TRUE|FALSE|\d+))(?:,\s*(?:'[^']*')|(?:TRUE|FALSE|\d+))*\)))$

Breakdown of the regex: #

• ^(\w+): Captures the key (one or more word characters: letters, digits, underscores)
• \s*=\s*: Matches the equals sign with optional whitespace around it (remove \s* if your input has no whitespace)
• The value group has three possible matches:
  1. (?:'[^']*'): A single quoted string (e.g., 'Yoda')
  2. (?:TRUE|FALSE|\d+): Unquoted boolean (TRUE/FALSE) or numeric value (e.g., 3, 72)
  3. (?:\((?:...)...\)): An array enclosed in parentheses, containing comma-separated elements (each element is either a quoted string, boolean, or numeric)

Step 3: Process Array Values #

For values wrapped in parentheses, you'll want to extract and clean the inner elements:

1. Strip the leading ( and trailing ) from the value
2. Split the inner string using the same top-level comma regex from Step 1
3. For each element:
   • If it starts and ends with ', strip the quotes to get the raw string
   • If it's TRUE/FALSE, convert to a boolean type
   • If it's digits, convert to a numeric type

Example Implementation (Python) #

Here's how you might turn this into working code to get a clean dictionary of key-value pairs:

import re

input_str = "TeacherName='Yoda',TeacherIsJedi=TRUE,TeachersAidNames=('Mace'),TeachersAidAlive=(FALSE),TeachersAidAges=(72),NumberOfStudents=3,StudentAges=(42,59,19)"

# Split into key-value pairs
pair_split_regex = r",(?=(?:[^']*'[^']*')*[^']*$)(?=(?:[^()]*\([^()]*\))*[^()]*$)"
pairs = re.split(pair_split_regex, input_str)

# Parse each pair into a dictionary
key_value_regex = r"^(\w+)\s*=\s*((?:'[^']*')|(?:TRUE|FALSE|\d+)|(?:\((?:(?:'[^']*')|(?:TRUE|FALSE|\d+))(?:,\s*(?:'[^']*')|(?:TRUE|FALSE|\d+))*\)))$"
result = {}

for pair in pairs:
    match = re.match(key_value_regex, pair)
    if not match:
        continue  # Skip invalid pairs if any
    
    key = match.group(1)
    value = match.group(2)
    
    # Handle array values
    if value.startswith('(') and value.endswith(')'):
        inner_content = value[1:-1].strip()
        elements = re.split(pair_split_regex, inner_content)
        processed_elements = []
        
        for elem in elements:
            elem = elem.strip()
            if elem.startswith("'") and elem.endswith("'"):
                processed_elements.append(elem[1:-1])
            elif elem == 'TRUE':
                processed_elements.append(True)
            elif elem == 'FALSE':
                processed_elements.append(False)
            elif elem.isdigit():
                processed_elements.append(int(elem))
        
        result[key] = processed_elements
    else:
        # Handle single values
        if value.startswith("'") and value.endswith("'"):
            result[key] = value[1:-1]
        elif value == 'TRUE':
            result[key] = True
        elif value == 'FALSE':
            result[key] = False
        elif value.isdigit():
            result[key] = int(value)

print(result)

Output: #

{
    'TeacherName': 'Yoda',
    'TeacherIsJedi': True,
    'TeachersAidNames': ['Mace'],
    'TeachersAidAlive': [False],
    'TeachersAidAges': [72],
    'NumberOfStudents': 3,
    'StudentAges': [42, 59, 19]
}

Notes: #

• This regex assumes boolean values are exactly TRUE/FALSE (uppercase). Adjust to (?:true|false|TRUE|FALSE) if you need to handle mixed/lowercase.
• Numeric values are treated as integers here. To support floats, modify the numeric part of the regex to \d+(?:\.\d+)? and update the processing code to use float() where appropriate.
• The regex handles optional whitespace around equals signs and commas in arrays—remove \s* if your input has no whitespace for better performance.

内容的提问来源于stack exchange，提问作者Kevin