正则表达式示例：
import re
my_str = "abcdefgfaabbbffbbbbbbfgbb"
len(max(re.compile("(b+b)*").findall(my_str))) #changed the regex from (b+b) to (b+b)*
# max([len(i) for i in re.compile("(b+b)").findall(my_str)]) also works
x=timeit.Timer(stmt='import itertools;my_str = "abcdefgfaabbbffbbbbbbfgbb";max(len(list(y)) for (c,y) in itertools.groupby(my_str) if c=="b")')
x.timeit()
22.759046077728271
x=timeit.Timer(stmt='import re;my_str = "abcdefgfaabbbffbbbbbbfgbb";len(max(re.compile("(b+b)").findall(my_str)))')
x.timeit()
8.4770550727844238
602392714
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