PHP implements array merging without functions

In PHP, array is an important data structure. Arrays can store multiple elements and can be manipulated using various functions. Among them, array merging is a common operation, usually implemented through the function array_merge(). However, sometimes we need to implement array merging manually without using built-in functions. This article describes how to implement array merging operations in PHP without using built-in functions.

Let’s first look at how to use the array_merge() function:

$array1 = array('a', 'b', 'c');
$array2 = array('d', 'e', 'f');
$array3 = array_merge($array1, $array2);

print_r($array3);

The running result is:

Array
(
    [0] => a
    [1] => b
    [2] => c
    [3] => d
    [4] => e
    [5] => f
)

As you can see, the array_merge() function merges two arrays into one and returns the result. Next, we will implement this process manually.

First, we need to define two arrays as follows:

$array1 = array('a', 'b', 'c');
$array2 = array('d', 'e', 'f');

Then, we create a new empty array $mergedArray to store the merged results:

$mergedArray = array();

Next, for each element in array $array1, add it to $mergedArray:

foreach ($array1 as $value) {
    $mergedArray[] = $value;
}

Similarly, for each element in array $array2, add it to $mergedArray Medium:

foreach ($array2 as $value) {
    $mergedArray[] = $value;
}

Finally, output $mergedArray to get the merged array:

print_r($mergedArray);

The complete code is as follows:

$array1 = array('a', 'b', 'c');
$array2 = array('d', 'e', 'f');
$mergedArray = array();

foreach ($array1 as $value) {
    $mergedArray[] = $value;
}

foreach ($array2 as $value) {
    $mergedArray[] = $value;
}

print_r($mergedArray);

Running results and using array_merge () function has the same result:

Array
(
    [0] => a
    [1] => b
    [2] => c
    [3] => d
    [4] => e
    [5] => f
)

As can be seen from the above example, although the method of manually implementing array merging is more complicated than the array_merge() function, in some cases, it is necessary. For example, if you need to write highly customized code and rely less and less on built-in functions, then implementing the code manually may be the best option.

Summary:

This article introduces how to implement array merging in PHP without using built-in functions. Although manually implementing array merging may be more complex than the array_merge() function, it also provides greater flexibility and customization. In order to make full use of the array functions in PHP, we need to learn to use various array operation functions and implement array operations manually.

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