Arrays irregulares y formato de tablas

Concepto de arrays irregulares

Crear un array irregular

public class Main {
  public static void main(String[] args) {
    // Create a jagged array with 3 rows of varying lengths
    int[][] m = new int[3][];

    // Row 0 has 2 columns
    m[0] = new int[]{1, 2};

    // Row 1 has 3 columns
    m[1] = new int[]{3, 4, 5};

    // Row 2 has 1 column
    m[2] = new int[]{6};

    // Print the jagged array
    System.out.println("Jagged array contents:");
    for (int r = 0; r < m.length; r++) {
      for (int c = 0; c < m[r].length; c++) {
        System.out.print(m[r][c] + " ");
      }
      System.out.println(); // new line after each row
    }
  }
}

Recorrido seguro

public class Main {
  public static void main(String[] args) {
    // Example jagged array
    int[][] m = {
      {1, 2},
      {3, 4, 5},
      {6}
    };

    // Safe nested loops for a jagged matrix
    for (int r = 0; r < m.length; r = r + 1) {
      // Always use the actual length of the current row
      for (int c = 0; c < m[r].length; c = c + 1) {
        int value = m[r][c];  // process the value
        System.out.print(value + " ");
      }
      System.out.println(); // new line after each row
    }
  }
}

Anchos de columna

// Determine the maximum number of columns among all rows
		int maxCols = 0;
		for (int r = 0; r < m.length; r = r + 1) {
		  if (m[r].length > maxCols) maxCols = m[r].length;
		}

		// For each column, store the maximum string length of values in that column
		int[] w = new int[maxCols];
		for (int r = 0; r < m.length; r = r + 1) {
		  for (int c = 0; c < m[r].length; c = c + 1) {
			int len = Integer.toString(m[r][c]).length();
			if (len > w[c]) w[c] = len;
		  }
		}

Impresión alineada

// Print each row with left-padded columns
		for (int r = 0; r < m.length; r = r + 1) {
		  String line = "";
		  for (int c = 0; c < m[r].length; c = c + 1) {
			String s = Integer.toString(m[r][c]);
			while (s.length() < w[c]) s = " " + s;  // left pad with spaces
			line = line + s + (c + 1 < m[r].length ? " " : "");
		  }
		  System.out.println(line);
		}

Demostración sin entrada

public class Main {
  // Compute per-column widths for a jagged matrix
  static int[] colWidths(int[][] m) {
    int maxCols = 0;
    for (int r = 0; r < m.length; r = r + 1) {
      if (m[r].length > maxCols) maxCols = m[r].length;
    }
    int[] w = new int[maxCols];
    for (int r = 0; r < m.length; r = r + 1) {
      for (int c = 0; c < m[r].length; c = c + 1) {
        int len = Integer.toString(m[r][c]).length();
        if (len > w[c]) w[c] = len;
      }
    }
    // Ensure at least width 1 for each column
    for (int c = 0; c < w.length; c = c + 1) {
      if (w[c] < 1) w[c] = 1;
    }
    return w;
  }

  // Print the matrix with aligned columns
  static void printTable(int[][] m) {
    int[] w = colWidths(m);
    for (int r = 0; r < m.length; r = r + 1) {
      String line = "";
      for (int c = 0; c < m[r].length; c = c + 1) {
        String s = Integer.toString(m[r][c]);
        while (s.length() < w[c]) s = " " + s;
        line = line + s + (c + 1 < m[r].length ? " " : "");
      }
      System.out.println(line);
    }
  }

  public static void main(String[] args) {
    // Sample jagged matrix (no Scanner; values are hard-coded)
    int[][] m = {
      {1, 23, 456},
      {7, 8},
      {90, 12, 3, 4}
    };

    System.out.println("Aligned table:");
    printTable(m);
  }
}

Comprobación del recorrido irregular

Repaso y siguiente paso