在C#中使用正则表达式解析含文本与正负数字的三段字符串

Got it, let's work through this regex problem step by step. Since you didn't share the exact structure of your target string, I'll start with a common, straightforward scenario where the text section comes first (with any number of words), followed by the two positive/negative numbers — and I’ll also show how to tweak things if your string has a different layout.

We need to capture three distinct parts: free-form text, a signed number, another signed number. Here's how to build the pattern:

Basic Version (Text First, Integers Only) #

This works for strings like "Quick brown fox -42 123" or "Hello -100 0":

^(.+?)\s+(-?\d+)\s+(-?\d+)$

Let’s break down each component:

• ^ & $: Anchors to match the entire string, so we don’t pick up partial matches
• (.+?): Non-greedy capture group for the text. The +? ensures we stop at the first whitespace before the first number (instead of gobbling up everything greedily)
• \s+: Matches one or more spaces to separate the text and numbers
• (-?\d+): Capture groups for the numbers. -? allows an optional negative sign, \d+ matches one or more digits (for integers)

Support for Decimal Numbers #

If your numbers can be decimals (like -3.14 or 2.718), adjust the number capture groups to handle decimal points:

^(.+?)\s+(-?\d+(\.\d+)?)\s+(-?\d+(\.\d+)?)$

The (\.\d+)? adds an optional decimal part to the number pattern.

Adjust for Different String Layouts #

If your numbers come before the text (e.g., "-10 20 Some random text here"), just reorder the capture groups:

^(-?\d+)\s+(-?\d+)\s+(.+)$

Here’s how to use this regex in practice to extract the three parts:

import re

# Example target string
target_string = "The quick brown fox jumps over the lazy dog -99 1234"

# Use the integer regex pattern
pattern = r"^(.+?)\s+(-?\d+)\s+(-?\d+)$"

match_result = re.match(pattern, target_string)
if match_result:
    extracted_text = match_result.group(1)
    first_number = int(match_result.group(2))
    second_number = int(match_result.group(3))
    
    print(f"Extracted Text: {extracted_text}")
    print(f"First Number: {first_number}")
    print(f"Second Number: {second_number}")
else:
    print("Error: String doesn't match the expected format!")

For decimals, just replace int() with float() and use the decimal regex pattern.

• Non-greedy matching is critical: Using (.+) instead of (.+?) would make the text capture group greedily consume everything up to the last number, breaking the match.
• Handle extra whitespace: If your string might have leading/trailing spaces, add \s* at the start and end of the regex: ^\s*(.+?)\s+(-?\d+)\s+(-?\d+)\s*$
• Text with numbers: If your text section includes numbers (e.g., "Text with 123 here -45 67"), you’ll need a clear separator (like | or ;) instead of spaces. For example, use ^(.+?)\|(-?\d+)\|(-?\d+)$ for strings formatted like "Text with 123 here|-45|67".

内容的提问来源于stack exchange，提问作者Bobbler