Check if letters that a word consists of are prese

2019-03-06 18:46发布

This is my first time posting here, so please tell me if I need to correct anything in this post. I'd like to ask for help with something that's been giving me some trouble. I need to check that the characters of one string appear in another string, but they need to be detected only once. For example, for the string "BFEABLDEG", "LABEL" should not return true, as it currently is doing.

For clarification, the aim is not to have the program count characters. It is to have the program check that the letters needed to create a word are contained in randomString, with the exact same number of each letter in both Strings. The program is partly based on the game show Countdown.

This is what I have so far. Any help would be greatly appreciated.

Edit: Thanks to everyone who helped me out with this. I've accepted Aru's contribution as the solution I was looking for as it avoids the problem I was having most accurately, given that the size of the string that needs to be checked.

public static boolean Checkword(){
String randomString = "BFEABLDEG";
 String word = "LABEL";
 {
 for(int i=0;i<word.length(); i++){
      if(randomString.contains(word.substring((i)))){
          return true;

      }
 }
return false;
 }

}

Ok, the solution I was given works for basic examples. However, the end goal was for the user to make words of any length from a string of nine random characters. Currently they can do this by putting in more occurences of any character than there are in the string. I was wondering if anyone could help me with this, given the new code that the function has been added to.

    public static boolean Checkword(String x){
    String randomString = convertToString();
     String word = x;
     {
     for(int i=0;i<word.length(); i++){
          if(randomString.indexOf(word.charAt(i)) == -1){
              return false;

          }
     }
    return true;
     }
}

3条回答
对你真心纯属浪费
2楼-- · 2019-03-06 18:59

It is returning true because your testing one char of randomString

public static boolean Checkword( String pattern, String randomString ){
  return ( randomString .contains( pattern ) ) ? true : false;
}

String pattern = "LABEL";

String randomString = "BFEABLDEG";
Checkword( pattern, randomString );
//return false

randomString = "AZDAZLABELIIDZA";
Checkword( pattern, randomString );
//return true
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放我归山
3楼-- · 2019-03-06 19:01

Your program as it is is returning true if any character in your word variable is contained in your randomString variable. Judging from your comments it sounds like you want to check if every character from your word string is contained within your randomString variable. Here is a slightly different approach.

public static boolean Checkword(){
    String randomString = "BFEABLDEG";
    String word = "LABEL";
    for(int i=0;i<word.length(); i++){
         if(randomString.indexOf(word.charAt(i)) != -1){
             //If the letter isn't contained return false
             return false;
          } else {
              //If the letter is contained remove it from the string
              int charLocation = randomString.indexOf(word.charAt(i));
              randomString = randomString.substring(0, charLocation) + randomString.substring(charLocation+1);
          }
    }
    //If I haven't returned yet, then every letter is contained, return true
    return true;
}

This is quite inefficient since it has to create a new string each time, if you want to make it a little better, use a string builder to mutate the string to remove the characters as they are found.

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姐就是有狂的资本
4楼-- · 2019-03-06 19:09

I'm not sure if I entirely understand what you're trying to achive, but the whole logic of your method is flawed.

One problem is, obviously, that your function will return true if just the last character matches, since substring(word.length() - 1) will check whether the last character is contained in the other string. In every other loop, you are checking whether an entire sequence is contained, starting with the entire string and reducing the amount of characters every loop.

Even if you add characters to word that are not in randomString, the function will return true as long as they are not at the end of the string.

Something like this should be what you were looking for originally:

public static boolean checkWord() {
    String randomString = "BFEABLDEG";
    String word = "LABEL";
    for (int i = 0; i < word.length(); i++) {
        if (randomString.indexOf(word.charAt(i)) == -1) {
            return false;
        }
    }
    return true;
}

A simple solution to also check for duplicated characters is to remove one occurrence of the character in the string. There are certainly more efficient solutions possible, make sure to check the thread linked in the comments.

public static void main(String[] args) throws Exception {
    System.out.println(test("BFEABLDEG", "LABEL"));
}

public static boolean test(String searchIn, String searchFor) {
    for (char c : searchFor.toCharArray()) {
        if (searchIn.indexOf(c) == -1) {
            return false;
        }
        searchIn = searchIn.replaceFirst(Character.toString(c), "");
    }
    return true;
}
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