with open("xxx.txt", "r+") as f:
   satirlar = f.readlines()
   secilen_satir = random.choice(satirlar)
   mail= secilen_satir.split(":")[0]
   sifre = secilen_satir.split(":")[1]
   print(mail + sifre)
   f.seek(0)
   for i in satirlar:
      if i != secilen_satir:
         f.write(i)
   f.truncate()