如何获取第n个匹配的行号？

import re

def get_nth_matching_line_number(text, pattern, n):
    lines = text.split('\n')
    match_count = 0
    line_number = 0

    for line in lines:
        line_number += 1
        if re.search(pattern, line):
            match_count += 1
            if match_count == n:
                return line_number
    
    return -1  # 如果找不到第n个匹配的行，返回-1或者其他自定义的错误码

# 示例用法
text = """
This is line 1.
This is line 2.
This is line 3.
This is line 4.
This is line 5.
"""

pattern = r"This is line"  # 匹配以"This is line"开头的行
n = 3  # 获取第3个匹配的行号

line_number = get_nth_matching_line_number(text, pattern, n)
if line_number != -1:
    print(f"The line number of the {n}th matching line is: {line_number}")
else:
    print(f"Cannot find the {n}th matching line.")