如何在c#中将字符串值与字符串数组的元素进行比较？ [复制]

Question

在以下程序中，我想检查（通过防御编程）用户是否输入（命名日） 匹配字符串数组的元素之一（命名为 weekdays）。

到目前为止，我已经完成了以下操作。任何人都可以提供帮助（以获得更好的解决方案）吗？谢谢。

....

string[] weekdays = new string[7] { "Monday", "Tuesday", "Wednesday",
            "Thursday", "Friday", "Saturday", "Sunday"};

      Console.WriteLine("Give me a day: ");
        String day= Console.ReadLine();


         for (i=0; i< weekdays.Length; i++)
        {
            if (weekdays[i] == day)
            {

                break;
            }
            else if (weekdays[i] != day && i==6)
            {
                Console.WriteLine("Try again");
                day = Console.ReadLine();
                i = -1;
            }
        }

Answer 1

可以使用Linq.Any()函数：

using System.Linq;
...

string[] weekdays = new string[7] { "Monday", "Tuesday", "Wednesday",
        "Thursday", "Friday", "Saturday", "Sunday"};

Console.WriteLine("Give me a day: ");
String day= Console.ReadLine();

//No need to iterate over array and check day exists in array or not.
//You can use .Contains() method as well.
if(weekdays.Any(x => x == day))   
     break;
else
{
      Console.WriteLine("Try again");
      day = Console.ReadLine();
}

如果您希望它在循环中，那么您可以根据您的要求使用while(<condition>) 或for 循环

From MSDN:

Linq Any() 方法：判断一个序列的任何元素是否存在 或满足条件。

---

您可以使用以下逻辑来执行相同的操作，而无需任何 linq 功能和简化的解决方案：

//Week days array
string[] weekdays = new string[7] { "Monday", "Tuesday", "Wednesday",
        "Thursday", "Friday", "Saturday", "Sunday"};

//While infinity loop to execute inner code till incorrect day enters like "hey" 
while(true)
{
   //Read first input from user
   Console.WriteLine("Give me a day: ");
   string day= Console.ReadLine();

   //flag to check user entered correct value or not
   bool isAvailable = false;
   foreach(var wday in weekdays)
   { 
      //If entered day is correct then set flag and exit from foreach loop 
      if(wday == day)
      {
         isAvailable = true;
         break;
      }
   }
   //Check flag and if entered value is wrong then read user input again.
   if(isAvailable)
      break;
   else
   {
      Console.WriteLine("Try again");
      day = Console.ReadLine();
   }
}