1. (2022高一下·三门期中) 有如下 Python 程序段：

s=”我爱 13aPP14LE！”

ans=res=""

for x in s:

  if "a"<=x<="z":

    ans=ans+chr(ord(x)-32)

    if "A"<=x<="Z":

      ans=ans+chr(ord(x)+32)

      if "0"<=x<="9":

        res=res+x t=ans+res

print(t)