Python 试图存储信息

我想将所有用户注册的ID保存到一个文本文件中。如果用户给出9个用户，那么我希望它存储所有信息。但当我运行代码并完成时，它似乎覆盖了所有信息。我知道我遗漏了一些东西。有人能帮我吗

student_count = int(input("how many students are registering?:"))
reg_form = []

for x in range(student_count):
    
   if student_count >= 0:
       registered_user = input("Please enter your I.D number for registeration: ")
       id_information = [registered_user + reg_form]
       student_count - 1
   
student_count2 = str(student_count)


with open ("reg_form.txt", 'w') as f:
     f.write(registered_user + "\n")
     
f.close()

试着这样做：

student_count = int(input("how many students are registering?:"))
counter = 0

for x in range(student_count):
    
   if counter < student_count + 1:
       registered_user = input("Please enter your I.D number for registeration: ")
       counter += 1


       reg_form = open('reg_form.txt', 'a') 
       reg_form.write(registered_user + "\n")
       reg_form.close()

---

谢谢你，你真的帮了我

open('reg_form.txt', 'a')