Java 使用数组连接字符串

Question

我知道有一个支持处理生物信息的包，例如 Biojava ，但我想编写一个简单的代码，将 DNA 序列转换为其补体序列

这是我的代码...

public class SeqComplement{
    static String sequence ;
    String Complement(String sequence){
        // this.sequence = sequence;
        // String complement;
        // complement = "N";
        // for(int i = 0 ; i< sequence.length() ; i++){
        String[] raw = new String[sequence.length()];
        String[] complement = new String[sequence.length()];
        String ComplementSeq = "N";
        for(int i = 0 ; i <sequence.length() ; i++){
            String sub = sequence.substring(i,i+1);
            raw[i] = sub;
            }
        for(int j = 0 ; j < sequence.length();j++){
            if(raw[j] == "A"){
                complement[j] = "T";
                }
            else if (raw[j] == "T"){
                complement[j] = "A";
                }
            else if (raw[j] == "G"){
                complement[j] = "C";
                }
            else if (raw[j] == "C"){
                complement[j] = "G";
                }
            else{
                complement[j] = "N";
                }
            }
        for(int k = 0 ; k < complement.length ; k++){
            ComplementSeq+=complement[k];
            }
        return ComplementSeq.substring(1);
        }


    public static void main(String[] args){
        SeqComplement.sequence = "ATCG";
        SeqComplement ob = new SeqComplement();
        System.out.println(ob.Complement(ob.sequence));
    }
}

此代码给出的结果为 NNNN

我已经尝试过使用 String.concat() 方法，但它没有给我任何结果。

Answer 1

要将字符串转换为字符数组，您应该使用以下代码:

char[] raw = sequence.toCharArray();
char[] complement = sequence.toCharArray();

此外，为了比较字符串，您不应该不使用==运算符，您应该在字符串上调用.equals方法。

另一个好的建议是使用 HashMap 来存储补集，如下所示:

HashMap<Character, Character> complements = new HashMap<>();
complements.put('A', 'T');
complements.put('T', 'A');
complements.put('C', 'G');
complements.put('G', 'C');

并像这样补充每个字符:

for (int i = 0; i < raw.length; ++i) {
    complement[i] = complements.get(raw[i]);
}

完整代码:

public class SeqComplement {
  private static HashMap<Character, Character> complements = new HashMap<>();
  static {
    complements.put('A', 'T');
    complements.put('T', 'A');
    complements.put('C', 'G');
    complements.put('G', 'C');
  }

  public String makeComplement(String input) {
    char[] inputArray = input.toCharArray();
    char[] output = new char[inputArray.length];

    for (int i = 0; i < inputArray.length; ++i) {
       if (complements.containsKey(inputArray[i]) {
         output[i] = SeqComplement.complements.get(inputArray[i]);
       } else {
         output[i] = 'N';
       }
     }

    return String.valueOf(output);
  }


  public  static void main(String[] args) {
    System.out.println(new SeqComplement().makeComplement("AATCGTAGC"));
  }
}