Python中移除字符串内EDIFACT消息的正则表达式实现需求

Got it, let's break down how to safely remove EDIFACT messages from a string using Python regex without accidentally deleting other content. EDIFACT messages follow a strict structure we can exploit to target only them.

Key Observations About EDIFACT Structure #

EDIFACT messages have consistent, identifiable markers:

• They start with the UNB segment (interchange header)
• They end with the UNZ segment (interchange trailer)
• Each segment in between ends with a single quote ('), and segments may be separated by whitespace (spaces, newlines, tabs, etc.)

The Regex Pattern #

We can build a regex that strictly matches this structure to avoid false positives:

UNB(?:[^']+'\s*)*UNZ[^']+'

Let's break down what each part does:

• UNB: Matches the mandatory start of an EDIFACT interchange
• (?:[^']+'\s*)*: A non-capturing group that matches any number of intermediate segments:
  • [^']+: Matches all characters in a segment (excluding the closing single quote)
  • ': Matches the segment's closing quote
  • \s*: Accounts for any whitespace (including newlines) between segments
  • *: Allows zero or more intermediate segments (valid EDIFACT will have at least some)
• UNZ[^']+': Matches the mandatory closing UNZ segment, including its content up to the final quote

Python Implementation #

Here's a reusable function to clean your text:

import re

def remove_edifact_content(input_text):
    # Define the EDIFACT-matching regex pattern
    edifact_regex = r'UNB(?:[^']+'\s*)*UNZ[^']+'
    # Replace all matched EDIFACT messages with an empty string
    cleaned_text = re.sub(edifact_regex, '', input_text)
    # Optional: Clean up leftover extra whitespace
    cleaned_text = re.sub(r'\s+', ' ', cleaned_text).strip()
    return cleaned_text

# Test with your sample content
sample_input = """Random text before EDIFACT UNB+AHBI:1+.? ' UNB+IATB:1+6XPPC:ZZ+LHPPC:ZZ+940101:0950+1' UNH+1+PAORES:93:1:IA' MSG+1:45' IFT+3+XYZCOMPANY AVAILABILITY' ERC+A7V:1:AMD' IFT+3+NO MORE FLIGHTS' ODI' TVL+240493:1000::1220+FRA+JFK+DL+400+C' PDI++C:3+Y::3+F::1' !ERC+21198:EC' APD+74C:0:::6++++++6X' TVL+240493:1740::2030+JFK+MIA+DL+081+C' PDI++C:4' APD+EM2:0:1630::6+++++++DA' UNT+13+1' UNZ+1+1' More random text after EDIFACT"""

print(remove_edifact_content(sample_input))
# Output: "Random text before EDIFACT More random text after EDIFACT"

Why This Won't Accidentally Delete Other Content #

This regex is intentionally strict: it only targets content that starts with UNB, follows the segment structure (each part ending with '), and ends with a UNZ segment. Any other text—even if it contains single quotes or random letters—won't match unless it fits this exact EDIFACT pattern.

内容的提问来源于stack exchange，提问作者Deepak Aggarwal