Learn to use PHP to insert elements at the specified position and key of the array

Function analysis

array_flip —  Swap keys and values in an array 
array_slice —  Take a segment from the array 

Sample code

/** * @param $input [ The array that needs to be modified ] * @param $offset [ After the starting position or key name of the insert ] * @param $length [ Inserted length or before key name ] * @param $replacement [ Elements to insert (array、string....)] * @return array */
function array_splice_assoc(&$input, $offset, $length = 0, $replacement = array())
{
    
    $replacement = (array)$replacement;
    $key_indices = array_flip(array_keys($input));

    if (isset($input [$offset]) & is_string($offset)) {
    
        $offset = $key_indices [$offset];
    }
    if (isset($input[$length]) && is_string($length)) {
    
        $length = $key_indices [$length] - $offset;
    }

    //  First take out the element before the adding position and merge it with the element to be added , Then take the elements after the addition position and merge them 
    $result = array_slice($input, 0, $offset, TRUE)
        + $replacement
        + array_slice($input, $offset + $length, NULL, TRUE);

    return $result;
}


$input_str = '{"member_name":" Wandering memory ","address":" Chaoyang District, Beijing Municipality ","create_time":"2022 year 03 month 03 Japan  13 when 12 branch 56 second ","sum_score":10,"284_answer_text":"A、 correct ( answer ：√ have to 5 branch )","285_answer_text":" Sima Qian ( answer ：√ have to 5 branch )","287_answer_text":"119( answer ：× have to 0 branch )"}';
$input = json_decode($input_str, true);

echo " Original array <pre>";
print_r($input );

$replacement = ['283_answer_text' => ' Li Bai '];
$offset = '284_answer_text';

// Interception length 
$length = 0;


$result = array_splice_assoc($input, $offset, $length, $replacement);

echo " New array <pre>";
print_r($result);

Print the results