>>> origin = "hello alex bcd alex lge alex acd 19">>> r=re.sub("aw+","999",origin,2)>>> r'hello 999 bcd 999 lge alex acd 19'
“aw+”：表示匹配以a开头的单词
"999"：表示替换成的值
origin：原始字符串
2：只匹配2个