python匹配字符串中某个词的开始位置和结束位置

import re
import sys

arr = []
sentence = str(sys.argv[1])
word = str(sys.argv[2])
rr = re.compile(word, re.I)  # 不区分大小写，这里是把匹配的词汇转为正则的形式，不转直接匹配，遇见特殊字符会匹配不到
for match in re.finditer(rr, sentence):
    print(match)
    obj = {"start": match.start() + 1, "end": match.end(), "length": match.end() - match.start()}
    arr.append(obj)
print(arr)