How to merge two arrays and concat the values with PHP - php

Question

I'm looking for an easy solution to create a little function to merge two arrays with value concat (I'm using it to create html tag attribute):
$default["class"] = "red";
$new["class"] = "green";
$new["style"] = "display:block"
The result:
$res["class"] = "red green";
$res["style"] = "display: block";
and one more option:
if the $new is not an array, just concat with the $default["class"] (if this exist), and the other side: if the $default is a simple string, convert to array: $default["class"] = $default;
I created a function but would like to use an easier, shorter way for that:
function attrMerge( $default, $new="" ){
$res = array();
if(!is_array($default)) {
$res["class"] = $default;
}
else {
$res = $default;
}
if( $new !== "" ){
if(!is_array($new)) {
if(isset($res["class"])){
$res["class"].= " ".$new;
}
}
else {
foreach($new as $key=>$value) {
if( isset($res[$key]) ) {
$res[$key].= " ".$value;
}
else {
$res[$key] = $value;
}
}
}
}
return $res;
}
$a = attrMerge("red", array("class"=>"green", "style"=>"display: block;"));

Answer 1

I think this is the function that you need. I have initialised the css classes and styles as empty and in depends what you pass into the function then you get the relevant array
/**
* This function returns an array of classes and styles
*
* #param $default
* #param $new
* #return array
*/
function attrMerge($default=null, $new=nul)
{
$result = array();
$result['class'] = "";
$result['style'] = "";
// add default class if exists
if (!empty($default) && is_string($default)) {
// $default is string
$result['class'] = $default;
}
if (!empty($default)
&& is_array($default)
) {
if (array_key_exists('class', $default)
&& !empty($default['class'])
) {
// $default['class'] exists and it's not empty
$result['class'] = $default['class'];
}
if (array_key_exists('style', $default)
&& !empty($default['style'])
) {
// $default['style'] exists and it's not empty
$result['style'] = $default['style'];
}
}
// add additional classes OR styles
if (!empty($new)) {
if(!is_array($new)) {
$result['class'] = empty($result['class'])
? $new
: $result['class'] . " " . $new;
} else {
foreach ($new as $key => $value) {
if (isset($result[$key])) {
$result[$key] = empty($result[$key])
? $value
: $result[$key] . " " . $value;
} else {
$result[$key] = $value;
}
}
}
}
return $result;
}

Answer 2

A way I believe suits your need, hopefully it's as adaptable and effecient as you were expecting.
$array1 = array(
'class' => 'class1',
'style' => 'display: none;'
);
$array2 = array(
'class' => 'class2'
);
$arrayFinal = arrayMerge($array1, $array2);
var_dump($arrayFinal);
function arrayMerge($arr1, $arr2 = ''){
// Array of attributes to be concatenated //
$attrs = array('class');
if(is_array($arr2)){
foreach($attrs as $attr){
if(isset($arr1[$attr]) && isset($arr2[$attr])){
// Not using .= to allow for smart trim (meaning empty check etc isn't needed //
$arr1[$attr] = trim($arr1[$attr] . ' ' . $arr2[$attr]);
}
}
}else{
$arr1['class'] = trim($arr1['class'] . ' ' . $arr2);
}
return $arr1;
}

Answer 3

$def = ['class' => 'red'];
$new = ['class' => 'green', 'style' => 'style'];
function to_array($in) {
return is_array($in) ? $in : ['class' => $in];
}
$def = to_array($def);
$new = to_array($new);
$res = $def;
array_walk($new, function ($val, $key) use (&$res) {
$res[$key] = trim(#$res[$key] . ' ' . $val);
});
var_dump($res);