php+key to array

In PHP programming, it is often necessary to convert a set of key-value pairs into an array. This process is relatively simple and only requires the use of some array operation functions of PHP.

Let’s introduce how to convert key-value pairs into arrays.

1. Use the array_combine function

The array_combine function is a very convenient array operation function in PHP. It can combine two arrays into a new array, in which the The value serves as the key name of the new array, and the value in the second array serves as the value of the new array.

We can use this function to convert a set of key-value pairs into an array.

The sample code is as follows:

$keyArr = array('key1', 'key2', 'key3');
$valueArr = array('value1', 'value2', 'value3');

$newArr = array_combine($keyArr, $valueArr);

print_r($newArr);

The output result is:

Array
(
    [key1] => value1
    [key2] => value2
    [key3] => value3
)

2. Use foreach loop

In addition to using the array_combine function, you can also use foreach loop To convert key-value pairs into arrays. The sample code is as follows:

$keyValueArr = array('key1'=>'value1', 'key2'=>'value2', 'key3'=>'value3');

$newArr = array();

foreach($keyValueArr as $key => $value) {
    $newArr[$key] = $value;
}

print_r($newArr);

The output result is:

Array
(
    [key1] => value1
    [key2] => value2
    [key3] => value3
)

In this example, we first create a $keyValueArr array, which is an array of key-value pairs. Then use a foreach loop to traverse the array, add each key-value pair to a new array $newArr one by one, and finally get a converted array.

3. Use array_reduce function

In addition to array_combine and foreach, you can also use the array_reduce function to convert key-value pairs into arrays.

The array_reduce function is a very useful array operation function. It can combine an array through a callback function and return a value.

We can use the array_reduce function to convert key-value pairs into arrays. The sample code is as follows:

$keyValueArr = array('key1'=>'value1', 'key2'=>'value2', 'key3'=>'value3');

$newArr = array_reduce( array_keys( $keyValueArr ), function( $result, $key ) use ( $keyValueArr ) {
    $result[$key] = $keyValueArr[$key];
    return $result;
}, array() );

print_r( $newArr );

The output result is:

Array
(
    [key1] => value1
    [key2] => value2
    [key3] => value3
)

In this example, we use array_reduce Function to iterate over an array and add key-value pairs to a new array. In the specific implementation, all key names in the $keyValueArr array are first obtained through the array_keys function, and then the key names are traversed through the array_reduce function and the key-value pairs are added to the new array one by one.

Although this method is more complicated, it may be more convenient in some special cases.

In summary, we have introduced three methods of converting key-value pairs into arrays in PHP. Different methods differ in implementation details, but their essence is the same. In actual programming, you can choose the appropriate method according to the specific situation.

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