Java Script 回圈，陣列，物件，判斷，階乘，查找-綜合運用合集

1. 輸出100個hello world.

   for (var i = 1; i <= 100; i++) {
    console.log("hello world");
   }

2. 創建一個包含1~100的陣列.

   var array = [];
   for (var i = 1; i <= 100; i++) {
     array.push(i);
   }
   console.log(array);

3. 定義一個陣列，遍歷輸出它的每一項.

   var array = [55, 45, 77, 88, 99, 101, 120];
   for (var i = 0; i < array.length; i++) {
    console.log(array[i]);
   }

4. 輸出1-100的所有奇數.

   for (var i = 1; i < 100; i++) {
    if (i % 2 !== 0) {
     console.log(i);
    }
   }

5. 定義一個陣列，輸出陣列中所有的奇數.

   var array = [44, 55, 23, 45, 77, 88];
   for (var i = 0; i < array.length; i++) {
    if (array[i] % 2 !== 0) {
     console.log(array[i]);
    }
   }

6. 定義一個陣列，找出所有的奇數，放入到一個新陣列中.

   var array1 = [44, 55, 23, 45, 77, 8];
   var array2 = [];
   for (var i = 0; i < array1.length; i++) {
    if (array1[i] % 2 !== 0) {
     array2.push(array1[i]);
    }
   }
   console.log(array2);

7. 1~100求和.

   var sum = 0;
   for (var i = 1; i <= 100; i++) {
    sum += i;
   }
   console.log(sum);

8. 求某個數的階乘.

   function factorial(n) {
    var result = 1;
    if (n < 1) {
     return 0;
    }
    for (var i = 1; i <= n; i++) {
     result *= i;
    }
    return result;
   }
   console.log(factorial(5));

9. 陣列求和.

   sum = 0;
   var array = [1, 2, 3, 4, 5];
   for (var i = 0; i <= array.length; i++) {
    sum += i;
   }
   console.log(sum);

10. 求陣列中的奇數的個數.

    var count = 0;
    var array = [1, 2, 3, 4, 6];
    for (var i = 0; i < array.length; i++) {
     if (array[i] % 2 !== 0) {
      count++;
     }
    }
    console.log(count);

11. 求陣列中的奇數和.

    var sum = 0;
    var array = [1, 2, 3, 4, 7];
    for (var i = 0; i < array.length; i++) {
     if (array[i] % 2 !== 0) {
      sum = sum + array[i];
     }
    }
    console.log(sum);

12. 陣列中是否存在某個數，輸出 是 或 否.

    var array = [77, 88, 66, 54, 32, 21, 1];
    var target = 1;
    var isFind = false;
    for (var i = 0; i < array.length; i++) {
     if (array[i] === target) {
      isFind = true;
      break;
     }
    }
    if ((isFind = true)) {
     console.log("是");
    } else {
     console.log("否");
    }

13. 陣列中是否存在某個數，如果存在，則輸出它所在的下標，如果不存在，則輸出-1.

    var array = [99, 55, 34, 25, 77, 65, 32];
    var target = 65;
    var index = -1;
    for (var i = 0; i < array.length; i++) {
     if (array[i] === target) {
      index = i;
      break;
     }
    }
    console.log(index);
    var array = [1, 2, 3, 477, 54, 88, 65];
    for (var i = 0; i < array.length; i++) {
     console.log(i);
    }

14. 找到陣列中第一個奇數和最后一個奇數，將它們求和.

    var array = [55, 44, 65, 1, 2, 7, 15];
    var sum = 0;
    var isFind = false;
    for (var i = 0; i < array.length; i++) {
     if (array[i] % 2 !== 0) {
      isFind = array[i];
     }
    }
    var last = false;
    for (var i = array.length - 1; i >= 0; i--) {
     if (array[i] % 2 !== 0) {
      last = array[i];
     }
     sum = isFind + last;
    }
    console.log(isFind, last, sum);

15. 有兩個陣列，看兩個陣列中是否都存在奇數，輸出 是 或 否.

    var array1 = [4, 44, 7, 10, 8, 22, 12];
    var array2 = [22, 80, 22, 31];
    var isFind1 = false;
    var isFind2 = false;
    for (var i = 0; i < array1.length; i++) {
     if (array1[i] % 2 !== 0) {
      isFind1 = array1[i];
      break;
     }
    }
    for (var i = 0; i < array2.length; i++) {
     if (array2[i] % 2 !== 0) {
      isFind2 = array2[i];
      break;
     }
    }
    if (isFind1 && isFind2) {
     console.log("是");
    } else {
     console.log("否");
    }

16. 輸出一個物件的所有鍵值對.

    var obj = {
     a: 23,
     c: "jk",
     p: "75",
    };
    for (var key in obj) {
     console.log(key + "=" + obj[key]);
    }

17. 計算物件中字串屬性的數量.

    var obj = {
     a: "55",
     jk: "45",
     oppo: "54",
     txp: 5,
    };
    var count = 0;
    for (var key in obj) {
     if (typeof obj[key] === "string") {
      count++;
     }
    }
    console.log(count);

18. 將一個物件所有的數字屬性，轉換為字串，并在其前面加上￥.

    var obj = {
     name: "xxx",
     balance: 199.8,
     taken: 3000,
    };
    var newobj = {};
    for (var key in obj) {
     var velue = obj[key];
     if (typeof velue === "number") {
      newobj[key] = "￥" + velue;
     } else {
      newobj[key] = velue;
     }
    }
    console.log(obj, newobj);

標籤：JavaScript

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