如何仅在函数中第三次尝试失败后才显示消息？

Question

以下代码包含使用函数式编程输入密码。

pw = 9999

for (i in 1:3){
pw_entered=as.numeric(readline("Please enter the password: "))

if (pw_entered==pw){
    print("The door is opened. Welcome!")
    break
    
} else {
    print("Password wrong. Please re-enter the password: ")
    
}
print("You have exceeded the maximum limit of three times. Try Later")
} 

输出是，

Please enter the password: 1
[1] "Password wrong. Please re-enter the password: "
[1] "You have exceeded the maximum limit of three times. Try Later"
Please enter the password: 2
[1] "Password wrong. Please re-enter the password: "
[1] "You have exceeded the maximum limit of three times. Try Later"
Please enter the password: 3
[1] "Password wrong. Please re-enter the password: "
[1] "You have exceeded the maximum limit of three times. Try Later"

我希望消息 You have exceeded the maximum limit of three times. Try Later 仅在第三次尝试失败后显示，而不是在第一次和第二次尝试失败后显示。

Answer 1

我建议使用while 循环，因为不能保证每次都必须运行 3 次（如果在第一次尝试时输入的密码正确）。

pw <- 9999
attempt <- 0
#Something which is not pw
pw_entered <- 0

while(pw_entered != pw && attempt < 3) {
   pw_entered = as.numeric(readline("Please enter the password: "))
   if (pw_entered==pw){
      print("The door is opened. Welcome!")
      break
   } 
   attempt <- attempt + 1
  if(attempt == 3)  {
     print("You have exceeded the maximum limit of three times. Try Later")
     break
  }
  else print("Password wrong. Please re-enter the password: ")
} 

#Round 1 - 
Please enter the password: 123
#[1] "Password wrong. Please re-enter the password: "
Please enter the password: 9999
#[1] "The door is opened. Welcome!"

#Round 2 - 
Please enter the password: 1234
#[1] "Password wrong. Please re-enter the password: "
Please enter the password: 21
#[1] "Password wrong. Please re-enter the password: "
Please enter the password: 23
#[1] "You have exceeded the maximum limit of three times. Try Later"