a="this is"b=list(a)print(b)回车['t', 'h', 'i', 's', ' ', 'i', 's']a="this is"b=a.split()print(b)回车['this', 'is']#以上是b=list(a)和b=a.split的区别#如何用find找到第二个i的索引a="this is i i"b=0count=1while True: b=a.find("i",b) if b==-1: break if count>1: break b+=1 count+=1 print(b)回车5 #用正则匹配邮箱是否正确import ree="854@qq.com"a=re.findall(r"[0-9a-zA-Z]+@[0-9a-zA-Z]+.[a-z]+",e)print(a)#用正则匹配身份证是否正确import ree="441502199402233049"a=re.findall(r"[1-8]\d{5}(?:19[0-9][0-9]|20[0-2][0-1]|20[0-1][2-9])(?:0[1-9]|1[0-2])(?:0[1-9]|1[0-9]|2[0-9]|3[0-1])[0-9X]+",e)print(a)