假設我有一個帶有 int 值的二維數組，我想用二維數組中的所有 int 值填充一個一維數組，我該怎么做呢？這是我嘗試過的，但是出了點問題，我不知道是什么..int[][] twoDimensionalArray = {{5, 2, 3, 1}, {4, 2, 6, 9}, {8, 9, 1, 8}};int[] oneDimensionalArray = new int[twoDimensionalArray.length * twoDimensionalArray.length];for (int i = 0; i < twoDimensionalArray.length; i++) { for (int j = 0; j < twoDimensionalArray.length; j++) { oneDimensionalArray[i] = twoDimensionalArray[i][j]; }}謝謝！
4 回答
猛跑小豬
TA貢獻1858條經驗 獲得超8個贊
我可以提出這樣的建議，
String[][] my2Darr = {{5, 2, 3, 1},
{4, 2, 6, 9},
{8, 9, 1, 8}};
List<String> list = new ArrayList<>();
for(int i = 0; i < my2Darr.length; i++) {
list.addAll(Arrays.asList(my2Darr[i])); // java.util.Arrays
}
String[] my1Darr = new String[list.size()];
my1Darr = list.toArray(my1Darr);
爪哇 8：
int[][] 2darr = {{5, 2, 3, 1},
{4, 2, 6, 9},
{8, 9, 1, 8}};
int[] 1darr = Stream.of(2darr ).flatMapToInt(IntStream::of).toArray();
System.out.println(Arrays.toString(1darr ));
楊__羊羊
TA貢獻1943條經驗 獲得超7個贊
int[][] twoDimensionalArray = {{5, 2, 3, 1},
{4, 2, 6, 9},
{8, 9, 1, 8}};
int[] oneDimensionalArray = new int[twoDimensionalArray.length * twoDimensionalArray.length];
for (int i = 0; i < twoDimensionalArray.length; i++) {
for (int j = 0; j < twoDimensionalArray[0].length; j++) {
oneDimensionalArray[i] = twoDimensionalArray[i][j];
}
}
您的解決方案幾乎是正確的。您必須更正twoDimensionalArray.length為twoDimensionalArray[0].length. 因為你想水平和垂直迭代。如果您在 twoDimensionalArray.length 上迭代 2 次，您將迭代 2 倍水平軸的長度。
函數式編程
TA貢獻1807條經驗 獲得超9個贊
您可以使用它，它用于System.arraycopy()將內部數組復制到結果中：
public static int[] flatten(int[][] input) {
int length = input.length;
if(length == 0) return new int[0];
int[] output = new int[length * input[0].length];
for(int i = 0; i < length; i++) {
int[] inner = input[i];
// 1. Parameter: the source to copy from
// 2. Parameter: the starting index from source
// 3. Parameter: the destionation to copy to
// 4. Parameter: the starting index from destination
// 5. Parameter: the amount of elements to copy
System.arraycopy(inner, 0, output, i * length, inner.length);
}
return output;
}
慕田峪7331174
TA貢獻1828條經驗 獲得超13個贊
您可以使用 來執行此操作stream，例如：
int[][] twoDimensionalArray = {{5, 2, 3, 1},
{4, 2, 6, 9},
{8, 9, 1, 8}};
int[] oneDimensionalArray = Arrays.stream(twoDimensionalArray)
.flatMapToInt(e -> Arrays.stream(e))
.toArray();
System.out.println(Arrays.toString(oneDimensionalArray));
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