如何打印二維數組中的第一個字符

Question

我正在嘗試將每個單詞的第一個字符打印到二維數組中。 當我嘗試使用 ZE83AED3DDF4667DEC0DAAAACB2BB3BE0BZ 打印它時出現錯誤。

String [][] manyWords = { 
        {"red", "bling", "grand"},
        {"bridge", "queen", "chair"}
    };
    System.out.print(manyWords.substring(0, 1));

我收到無法編譯的源代碼錯誤。

Answer 1

你必須使用一些循環（我更喜歡 for-each 而不是 for/while）：

for(String[] strArr : manyWords){
   for(String str : strArr){
       System.out.println(str.substring(0,1);}}

Answer 2

以下代碼應該可以實現您的目標：

    public class test{

      public static void main(String[] args){

    // Declare test array
    String [][] manyWords = { 
            {"red", "bling", "grand"},
            {"bridge", "queen", "chair"}
        };

    // Since it is a 2d array, loop through it with both an x and y coordinate
    // Check https://stackoverflow.com/questions/25798958/iterate-through-2-dimensional-array for more info
    for (int i = 0; i < manyWords.length; i++){
      for (int j = 0; j < manyWords[i].length; j++){

        // Set the current character using charAt
        char curr = manyWords[i][j].charAt(0);

        // Print it out
        System.out.println(curr);

      } //end inner for
    } //end outer for
  } //end psvm
} //end class

印刷：

r
b
g
b
q
c

Answer 3

這是 stream 版本：

Stream.of(manyWords).flatMap(Stream::of).map(s -> s.substring(0, 1))
    .forEach(System.out::print);

Answer 4

你可以這樣做。 我希望這對你有幫助。

String [][] manyWords = { {"red", "bling", "grand"}, {"bridge", "queen", "chair"} };

for (int i = 0; i < manyWords.length; i++) {
   for (int j = 0; j < manyWords[i].length; j++) {
          System.out.print(manyWords[i][j].substring(0, 1) + " ");
   }
}