Shifting specific index's in array to front based on value inside - php

Question

I have the following array.
{
"flow":[
{
"tasks":[
{ "id":"1", "uid":"bryan" },
{ "id":"2", "uid":"eric" }
]
},
{
"tasks":[
{ "id":"1", "uid":"bryan" },
{ "id":"2", "uid":"eric" }
]
},
{
"tasks":[
{ "id":"1", "uid":"bryan" },
{ "id":"2", "uid":"eric" }
]
},
{
"tasks":[
{ "id":"1", "uid":"bryan" },
{ "id":"2", "uid":"eric" },
{ "id":"3", "uid":"eric" },
{ "id":"4", "uid":"bryan" }
]
}
]
}
Let's say I am eric. If I am eric, I am trying to move all items with the uid of eric to the front of the tasks array.
So that the array would end looking like this:
{
"flow":[
{
"tasks":[
{ "id":"2", "uid":"eric" },
{ "id":"1", "uid":"bryan" }
]
},
{
"tasks":[
{ "id":"2", "uid":"eric" },
{ "id":"1", "uid":"bryan" }
]
},
{
"tasks":[
{ "id":"2", "uid":"eric" },
{ "id":"1", "uid":"bryan" }
]
},
{
"tasks":[
{ "id":"2", "uid":"eric" },
{ "id":"3", "uid":"eric" },
{ "id":"1", "uid":"bryan" },
{ "id":"4", "uid":"bryan" }
]
}
]
}
I've attempted to make a function to do it, but for some reason it's not working the way I intended it to. Does anyone know what I'm doing wrong?
function reorder_flow($flow, $uid)
{
foreach($flow as &$step)
{
//step is the array with tasks
$tasks = $step['tasks'];
$new_tasks = array();
foreach($tasks as $key => $t)
{
if($t['uid'] == $uid)
{
$new_tasks = $new_tasks + $t;
unset($tasks[$key]);
}
}
$step['tasks'] = $new_tasks + $step['tasks'];
}
return $flow;
}

Answer 1

This is a traversal/sorting problem.
$json = <<<JSON
{
"flow":[
{
"tasks":[
{ "id":"1", "uid":"bryan" },
{ "id":"2", "uid":"eric" }
]
},
{
"tasks":[
{ "id":"1", "uid":"bryan" },
{ "id":"2", "uid":"eric" }
]
},
{
"tasks":[
{ "id":"1", "uid":"bryan" },
{ "id":"2", "uid":"eric" }
]
},
{
"tasks":[
{ "id":"1", "uid":"bryan" },
{ "id":"2", "uid":"eric" },
{ "id":"3", "uid":"eric" },
{ "id":"4", "uid":"bryan" }
]
}
]
}
JSON;
$flow = json_decode($json, true);
array_walk($flow['flow'], function(&$flowItem, $key){
usort($flowItem['tasks'], function($a, $b){
$aIsMatch = $a['uid'] === 'eric';
$bIsMatch = $b['uid'] === 'eric';
if ($aIsMatch && $bIsMatch) {
return 0;
}
if ($aIsMatch) {
return -1;
}
if ($bIsMatch) {
return 1;
}
// Fallback sorting criteria - you could use something else or just return 0
return strcasecmp($a['uid'], $b['uid']);
});
});
echo json_encode($flow, JSON_PRETTY_PRINT);

Answer 2

Please try this:
function sortByUID(&$array, $uid) {
array_walk ($array, function($obj) use($uid) {
uasort($obj->tasks, function($a, $b) use($uid) {
return $a->uid == $uid ? -1 : 1;
});
});
}
sortByUID($data->flow, 'eric');
Demo: https://3v4l.org/mOhDX
I hope this will help.

Answer 3

notes:
+ does not work with arrays in that way
json_decode should have the second parameter set to true to get nested arrays
then try this in the foreach:
//step is the array with tasks
$new_tasks=array();
foreach($step['tasks'] as $t){
if($t['uid'] == $uid){
array_unshift($new_tasks,$t);
} else {
array_push($new_tasks,$t);
}
}
$step['tasks'] = $new_tasks;