Search in Array

// Method 1: Using indexOf
let arr = [10, 20, 30, 40, 50];
let searchValue = 30;

let index = arr.indexOf(searchValue);
if (index !== -1) {
    console.log(`${searchValue} found at index ${index}`);
} else {
    console.log(`${searchValue} not found`);
}

// Method 2: Using includes
let numbers = [5, 10, 15, 20, 25];
console.log("\nUsing includes:");
console.log("15 exists:", numbers.includes(15));
console.log("35 exists:", numbers.includes(35));

// Method 3: Using find
let users = [
    { id: 1, name: "John" },
    { id: 2, name: "Jane" },
    { id: 3, name: "Bob" }
];

let user = users.find(u => u.id === 2);
console.log("\nUsing find:", user);

// Method 4: Using findIndex
let index2 = users.findIndex(u => u.name === "Bob");
console.log("\nFindIndex:", index2);

// Method 5: Using for loop
function searchArray(arr, value) {
    for (let i = 0; i < arr.length; i++) {
        if (arr[i] === value) {
            return i;
        }
    }
    return -1;
}

console.log("\nUsing loop:", searchArray([1, 2, 3, 4, 5], 3));

// Method 6: Binary search (sorted array)
function binarySearch(arr, target) {
    let left = 0;
    let right = arr.length - 1;
    
    while (left <= right) {
        let mid = Math.floor((left + right) / 2);
        
        if (arr[mid] === target) {
            return mid;
        } else if (arr[mid] < target) {
            left = mid + 1;
        } else {
            right = mid - 1;
        }
    }
    return -1;
}

let sorted = [1, 3, 5, 7, 9, 11, 13];
console.log("\nBinary search:", binarySearch(sorted, 7));

// Method 7: Using some (check existence)
let hasEven = [1, 3, 5, 7, 8].some(num => num % 2 === 0);
console.log("\nHas even number:", hasEven);