Creating a Multi-dimensional Array Based on Known Keys Only - php

Question

I am attempting to convert a string into a multi-dimensional array with keys that are only allowed.
Given the string:
"type:blue, type:red, shift:second, shift:first, category:circle, system:unknown"
With the only possible keys:
$possibleKeys = [ "category", "shift", "type" ];
Create the array:
$searchArray = array( "type" => [ "blue", "red" ],
"shift" => [ "second", "first" ],
"category" => [ "circle" ]
);
So system:unknown is not added to the $searchArray as it is not in the $possibleKeys array.
Here is my code:
$myString = "type:blue, type:red, shift:second, shift:first, category:circle, system:unknown";
$params = explode( ",", $myString );
$possibleKeys = [ "category", "shift", "type", "chances" ];
$nodes = [];
foreach ($params as $param) {
$node = explode( ":", $param );
if (array_key_exists( $node[ 0 ], $nodes ) && in_array( $node[ 0 ], $possibleKeys )) {
array_push( $nodes[ $node[ 0 ] ], $node[ 1 ] );
} else {
$nodes[ $node[ 0 ] ] = $node[ 1 ];
}
}
But when I var_dump the array is garbage and some keys have extra spaces.
array(4) {
["type"]=>
string(9) "blue"
[" type"]=>
string(8) "red"
[" shift"]=>
string(5) "first"
[" category"]=>
string(3) "circle"
}
What am I doing wrong?

Answer 1

First build your associative array with your allowed keys.
Break your string up - first explode into an array by comma delimiter to get your pairs, then trim and explode each pair. If the left side is an allowed key, add the right side to the associative array element. As usual more than one way to do it, but this is what my current caffeine levels call for...
<?php
$dataString="type:blue, type:red, shift:second, shift:first, category:circle, system:unknown";
$desiredResult=array();
foreach(array("category", "shift", "type") as $desiredKey){
$desiredResult[$desiredKey]=array();
}
$tmpArr=explode(",",$dataString);
foreach($tmpArr as $pair){
$pair=trim($pair);
$pairArr=explode(":",$pair);
if(isset($desiredResult[$pairArr[0]])){
$desiredResult[$pairArr[0]][]=$pairArr[1];
}
}
print_r($desiredResult);
?>
Gives
Array
(
[category] => Array
(
[0] => circle
)
[shift] => Array
(
[0] => second
[1] => first
)
[type] => Array
(
[0] => blue
[1] => red
)
)

Answer 2

You can use regex to find the values and loop only the possible keys.
This means it only does three iterations to find all values and put them in the array.
The preg_match will find all words connected to the key in the full string.
$myString = "type:blue, type:red, shift:second, shift:first, category:circle, system:unknown";
$possibleKeys = [ "category", "shift", "type" ];
foreach($possibleKeys as $key){
preg_match_all("/" . $key . ":(.*?),/", $myString, $m);
$new[$key] = $m[1]; // $m[1] will hold all the matching values to the key searched for
}
var_dump($new);
The output is:
array(3) {
["category"]=>
array(1) {
[0]=>
string(6) "circle"
}
["shift"]=>
array(2) {
[0]=>
string(6) "second"
[1]=>
string(5) "first"
}
["type"]=>
array(2) {
[0]=>
string(4) "blue"
[1]=>
string(3) "red"
}
}
https://3v4l.org/XAeRC

Answer 3

Because you explode with "," try to explode with ", " (comma space) instead.

Answer 4

You can do small tweaks with your code and avoid some extra method using like trim() or array_key_exits()
<?php
$myString = "type:blue, type:red, shift:second, shift:first, category:circle, system:unknown";
$params = explode( ", ", $myString ); // explode by comma & space with
$possibleKeys = [ "category", "shift", "type", "chances" ];
$ignore = ['system'];
$nodes = [];
foreach ($params as $param) {
$node = explode( ":", $param );
if (in_array( $node[0], $possibleKeys )) {
$nodes[$node[0]][] = $node[1];
} else {
$nodes[$node[0]] = $node[1];
}
}
foreach($ignore as $key) {
unset($nodes[$key]);
}
print '<pre>';
print_r($nodes);
print '</pre>';
?>
DEMO: https://3v4l.org/Udav9