Advanced-JavaScript-With-Projects/array.html at main · marleyDip/Advanced-JavaScript-With-Projects · GitHub

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<!DOCTYPE html>
<html lang="en">
  <head>
    <meta charset="UTF-8" />
    <meta name="viewport" content="width=device-width, initial-scale=1.0" />
    <title>Array</title>
  </head>
  <body></body>
  <script>
    // let l = [1, 3, 7, 7, 74, 74];
    // console.log(l);
    // console.log(l[0]);
    // console.log(l[5]);

    // let i = new Array(1, 4, "hello", "deep", 4, 67);
    // console.log(i);
    // console.log(i[2]);
    // console.log(i[5]);

    //but in the case its not same....so new Array does not use

    /* let i2 = [10];
    console.log(i2);
    console.log(i2[0]);

    let i3 = new Array(10);
    console.log(i3);
    console.log(i3[0]); */ // undefined

    // multi-dimensional array
    //

    // let p = [10, 20, 30, 88, 77, 66, 55];
    // let t = p.length;

    // // length() is not method...length is method

    // console.log(t);
    // console.log(p.reverse());
    // console.log(p.reverse().join(", "));

    // for (let i = 0; i < t; i++) {
    //   console.log(i, p[i]);
    //   console.log(p[i]);
    //   // 0 p[0] = 10
    //   // 1 p[1] = 20
    // }

    // // console.log(i, p[i]);
    // // ReferenceError: i is not defined
    // // Js is interpreted language, if i can't comment the error then next for loop can't execute

    // for (let i = t - 1; i >= 0; i--) {
    //   console.log(i, p[i]);
    // }

    /* for...of = its only work in array & string...it can't work with object{}, its used for access array values */

    let p = [10, 20, 30, 88, 77, 66, 55];

    for (let v of p) {
      console.log(v);
    }

    const matrix = [
      [1, 2, 3],
      [4, 5, 6],
      [7, 8, 9],
    ];

    for (const row of matrix) {
      console.log(row);
      // [1, 2, 3]
      // [4, 5, 6]
      // [7, 8, 9]
    }

    for (const row of matrix) {
      for (const cell of row) {
        console.log(cell);
        // 1
        // 2 ... 9
      }
    }

    /* compare with forEach => for...of improve code readability, especially when dealing with nested structures or complex operations */
    matrix.forEach((row) => {
      row.forEach((cell) => {
        console.log(cell);
      });
    });

    /*
      Breaking and Continuing Loops => These features make for...of more powerful and versatile for complex iteration logic.
    */

    const number = [1, 2, 3, 4, 5];

    for (const number of numbers) {
      if (number === 3) {
        break;
      }
      console.log(number); // 1, 2
    }

    for (const number of numbers) {
      if (number === 3) {
        continue;
      }
      console.log(number); // 1, 2, 4, 5
    }

    // here p values 10, 20, ... store or pass in v
    //  array is special kind of object, so it gives object values one by one, not object numbered index

    /* for...in = it uses in object for access key - value pair....mainly in array it used for access number index, generally not array */

    for (let k in p) {
      console.log(k, p[k]);
    }
  </script>
</html>