检查字符串是否以Java中的任何给定前缀开头

给定一个字符串和一个前缀数组。任务是检查给定的字符串是否以任何给定的前缀开头。

例子：

Input: String = “GeeksforGeeks”, Prefixes = {“Geeks”, “for”, “Gfor”}
Output: true

Input: String = “GeeksforGeeks”, Prefixes = {“Freaks”, “for”, “Freak”}
Output: false

以下是可用于完成给定任务的以下方法：

1. 天真的方法：此方法涉及显式检查每个前缀数组元素的字符串。

   算法：

   1. 获取要匹配的字符串和前缀。
   2. 使用循环，遍历前缀并检查字符串是否以相应的前缀开头。这是在 String.startsWith() 方法的帮助下完成的。
   3. 如果匹配任何前缀，则返回 true，否则返回 false。

   方案一：

   class PrefixSearch {
       public static void main(String[] args)
       {
           // Array of prefixes
           String[] arr = { "Geeks", "for", "Gfor" };
     
           // Given string
           String str = "GeeksforGeeks";
     
           boolean result = false;
     
           // Check for each prefix element
           for (int i = 0; i < 3; i++) {
               if (str.startsWith(arr[i])) {
                   result = true;
                   break;
               }
           }
     
           if (result)
               System.out.println("Given String "
                                  + "starts with one of the prefixes.");
           else
               System.out.println("Given String do not "
                                  + "starts with one of the prefixes.");
       }
   }
   

   输出：

   Given String starts with one of the prefixes.
   

   方案二：

   class PrefixSearch {
       public static void main(String[] args)
       {
           // Array of prefixes
           String[] arr = { "Freaks", "for", "Freak" };
     
           // Given string
           String str = "GeeksforGeeks";
     
           boolean result = false;
     
           // Check for each prefix element
           for (int i = 0; i < 3; i++) {
               if (str.startsWith(arr[i])) {
                   result = true;
                   break;
               }
           }
     
           if (result)
               System.out.println("Given String "
                                  + "starts with one of the prefixes.");
           else
               System.out.println("Given String do not "
                                  + "starts with one of the prefixes.");
       }
   }
   

   输出：

   Given String do not starts with one of the prefixes.
   

2. 使用正则表达式：

   算法：

   1. 获取要匹配的字符串和前缀。
   2. 形成一个正则表达式来检查字符串是否以任何前缀开头。这可以使用 String.matches() 方法来完成。
   3. 如果匹配任何前缀，则返回 true，否则返回 false。

   方案一：

   class PrefixSearch {
       public static void main(String[] args)
       {
           // Array of prefixes
           String[] arr = { "Geeks", "for", "Gfor" };
     
           // Given String
           String str = "GeeksforGeeks";
     
           // Check for prefixes using Regex
           if (str.matches("(" + arr[0] + "|"
                           + arr[1] + "|"
                           + arr[2] + ").*"))
               System.out.println("Given String "
                                  + "starts with one of the prefixes.");
           else
               System.out.println("Given String do not "
                                  + "starts with one of the prefixes.");
       }
   }
   

   输出：

   Given String starts with one of the prefixes.
   

   方案二：

   class PrefixSearch {
       public static void main(String[] args)
       {
           // Array of prefixes
           String[] arr = { "Freaks", "for", "Freak" };
     
           // Given String
           String str = "GeeksforGeeks";
     
           // Check for prefixes using Regex
           if (str.matches("(" + arr[0] + "|"
                           + arr[1] + "|"
                           + arr[2] + ").*"))
               System.out.println("Given String "
                                  + "starts with one of the prefixes.");
           else
               System.out.println("Given String do not "
                                  + "starts with one of the prefixes.");
       }
   }
   

   输出：

   Given String do not starts with one of the prefixes.
   

3. 使用Java 8 流 API ：

   算法：

   1. 获取要匹配的字符串和前缀。
   2. 将前缀转换为流使用 Stream.of()
   3. 使用 Predicate str::startsWith 检查是否有任何前缀匹配。这是使用 Stream.anyMatch() 方法完成的。
   4. 如果匹配任何前缀，则返回 true，否则返回 false。

   方案一：

   import java.util.stream.Stream;
     
   class PrefixSearch {
       public static void main(String[] args)
       {
           // Array of prefixes
           String[] arr = { "Geeks", "for", "Gfor" };
     
           // Given String
           String str = "GeeksforGeeks";
     
           // Convert the Prefixes into Stream using Stream.of()
           // and check if any prefix matches using Predicate
           // str::startsWith
           if (Stream.of(arr)
                   .anyMatch(str::startsWith))
               System.out.println("Given String "
                                  + "starts with one of the prefixes.");
           else
               System.out.println("Given String do not "
                                  + "starts with one of the prefixes.");
       }
   }
   

   输出：

   Given String starts with one of the prefixes.
   

   方案二：

   import java.util.stream.Stream;
     
   class PrefixSearch {
       public static void main(String[] args)
       {
           // Array of prefixes
           String[] arr = { "Freaks", "for", "Freak" };
     
           // Given String
           String str = "GeeksforGeeks";
     
           // Convert the Prefixes into Stream using Stream.of()
           // and check if any prefix matches using Predicate
           // str::startsWith
           if (Stream.of(arr)
                   .anyMatch(str::startsWith))
               System.out.println("Given String "
                                  + "starts with one of the prefixes.");
           else
               System.out.println("Given String do not "
                                  + "starts with one of the prefixes.");
       }
   }
   

   输出：

   Given String do not starts with one of the prefixes.