How to Merge Two Arrays in PHP?

Introduction:
Merging arrays is a common task in PHP programming. Whether you’re combining data from two sources, creating complex datasets, or handling user inputs, understanding how to merge arrays is essential. In this tutorial, we will walk you through different techniques to merge two arrays in PHP, along with examples and use cases.

1. Using the array_merge() function:
   The array_merge() function is a straightforward way to combine two or more arrays into a single array. It appends the elements of one array to another, maintaining numeric keys.
   $array1 = [1, 2, 3];
$array2 = [4, 5, 6];
$mergedArray = array_merge($array1, $array2);
// Result: [1, 2, 3, 4, 5, 6]
2. Merging with the + operator:
   The + operator can also be used to merge arrays. It combines the arrays while preserving the keys of the first array. Keys that exist in both arrays will not be overwritten.
   $array1 = ['a' => 1, 'b' => 2];
$array2 = ['b' => 3, 'c' => 4];
$mergedArray = $array1 + $array2;
// Result: ['a' => 1, 'b' => 2, 'c' => 4]
3. Combining arrays using the array_merge_recursive() function:
   When dealing with arrays containing the same keys, but with different values, array_merge_recursive() comes in handy. It merges arrays recursively, combining their values into arrays even if they have the same keys.
   $array1 = ['a' => 1, 'b' => 2];
$array2 = ['b' => 3, 'c' => 4];
$mergedArray = array_merge_recursive($array1, $array2);
/* Result:
[
'a' => [1],
'b' => [2, 3],
'c' => [4]
]
*/
4. Merging arrays with array union (array_union()):
   In scenarios where you want to merge arrays without overwriting values, you can define a custom function for array union.
   function array_union($arr1, $arr2) {
return array_unique(array_merge($arr1, $arr2));
}
$array1 = [1, 2, 3];
$array2 = [3, 4, 5];
$mergedArray = array_union($array1, $array2);
// Result: [1, 2, 3, 4, 5]

Remember, the choice of method depends on your specific requirements. Understanding these techniques will empower you to efficiently manipulate arrays and create dynamic and flexible PHP applications. Happy coding!