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Discover how to easily merge two arrays in PHP and extract only the duplicate values, using simple methods and clear examples.
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How to Merge Two Arrays and Keep Only Duplicates in PHP

When working with arrays in PHP, there often comes a time when you need to merge two arrays but only keep the duplicate values. The challenge is to identify common elements between two sets of data. In this guide, we will explore two different approaches to achieve the desired result.

The Problem: Merging Arrays to Find Duplicates

Let's say you have the following two arrays:

[[See Video to Reveal this Text or Code Snippet]]

Your objective is to merge these two arrays and obtain an array that contains only the elements available in both arrays. For the above arrays, the expected output should be:

[[See Video to Reveal this Text or Code Snippet]]

So, how can you do this quickly and easily?

Solution Approach

We will explore two different methods for merging these arrays and extracting the duplicate values.

Option 1: Using array_intersect()

The first method takes advantage of PHP's built-in function array_intersect(). This function compares the values of the two arrays and returns the values that are present in both.

Example Code

Here’s how you can implement this:

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Output

The output from the above code will be:

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Note: The keys of the resulting array will retain their original keys from the first array.

Option 2: Using a Loop with in_array()

If you prefer a more manual approach, you can achieve the same result using a loop and the in_array() function. This method involves iterating through each element of the first array and checking if it exists in the second array.

Example Code

Here’s how you can do this:

[[See Video to Reveal this Text or Code Snippet]]

Output

The output from this second approach will yield:

[[See Video to Reveal this Text or Code Snippet]]

Note: In this case, the array index starts from 0 as it is a newly created array.

Conclusion

Both methods presented above effectively merge two arrays and extract only the duplicate values. Depending on your preference, you can choose the built-in function or implement a custom loop.

By mastering these techniques, you will enhance your PHP programming skills and efficiently handle array manipulations in your projects. Happy coding!