正则表达式来查找字符串的最后一个实例

import re

def find_last_instance(text, pattern):
    # 使用负向零宽断言查找最后一个实例
    regex = re.compile(f'(?<!{pattern}).*{pattern}')
    match = regex.search(text)
    if match:
        return match.group(0)
    return None

text = "hello world, hello universe, hello everyone"
pattern = "hello"
print(find_last_instance(text, pattern))  # 输出: "hello everyone"

import re

def find_last_instance(text, pattern):
    # 使用反向查找查找最后一个实例
    regex = re.compile(f'{pattern}(?!.*{pattern})')
    match = regex.search(text)
    if match:
        return match.group(0)
    return None

text = "hello world, hello universe, hello everyone"
pattern = "hello"
print(find_last_instance(text, pattern))  ### 输出: "hello everyone"

import re

def find_last_instance(text, pattern):
    regex = re.compile(f'(?<!{pattern}).*{pattern}')
    match = regex.search(text)
    if match:
        return match.group(0)
    return None

text = "hello world, hello universe, hello everyone"
pattern = "hello"
print(find_last_instance(text, pattern))  # 输出: "hello everyone"