Get previous and next values in array - php

Question

I have array, for example:
<?php
$array = array(
0 => array(
'subject' => 'Stackoverflow',
'body' => '',
'name' => 'php'
),
1 => array(
'subject' => 'Test',
'body' => 'Wayne',
'name' => ''
),
2 => array(
'subject' => '',
'body' => 'this is ok',
'name' => ''
),
3 => array(
'subject' => 'cnn',
'body' => 'Google',
'name' => 'private'
),
4 => array(
'subject' => 'code',
'body' => '',
'name' => '7777'
)
);
And i would like get subject, body and name for key 2 and if key not exist then this should get from previous and next (separate function) values.
For example if i want get value from 2 key:
function getCurrentOrPrevious(2);
should return:
array(
'subject' => 'Test', //from [1]
'body' => 'this is ok', //from [2] - current and exist
'name' => 'php' //from [0] - in from [2] and [1] not exist
)
function getCurrentOrNext(2);
should return:
array(
'subject' => 'cnn', //from [3]
'body' => 'this is ok', //from [2] - current
'name' => 'php' //from [3]
)
How is the best way for this? Are there any functions in PHP for such operations?
LIVE

Answer 1

Assuming, you fill your array similar to $array[] = $value; [i.e. that you have consecutive numeric keys starting from zero]:
## $array is the array to take values from, $key is the target key
## $fields are required fields
function getCurrentOrPrevious($array, $key, $fields) {
if ($key < 0) return null;
$output = array();
foreach ($fields as $field) {
for ($i = $key; $i >= 0; $i--) {
if (!empty($array[$i][$field])) {
$output[$field] = $array[$i][$field];
break;
}
}
return $output;
}
Use as follows:
$my_values = getCurrentOrPrevious($array, 12, array('subject', 'body', 'name'));

Answer 2

I guess you could use empty() function of php to check. Also you should think about how far that function shell go?
What if [3] (next) also has an empty value at the same position
What if previous index is <0?
UPDATE
function getCurrOrNext($array, $index){
$keys = array_keys($array[$index]);
foreach($keys AS $key){
if($array[$index][$key] == "") {
$array[$index][$key] = (!empty($array[$index+1]) && !empty($array[$index+1][$key])?$array[$index+1][$key]:null);
}
}
return $array;
}
I guess something like this

Answer 3

function getCurrentOrPrev($array, $key) {
while(key($array)!==$key) next($array); //move internal pointer to required position first
$result = current($array);
//loop is going to execute as long as at least one of elements is empty and we didn't get to beginning of array yet
while((empty($result['subject'])
|| empty($result['body'])
|| empty($result['name']))
&& prev($array)!==false) {
$c = current($array);
//replace empty elements with values of current element
$result['subject'] = empty($result['subject']) ? $c['subject'] : '';
$result['body'] = empty($result['body']) ? $c['body'] : '';
$result['name'] = empty($result['name']) ? $c['name'] : '';
}
return $result;
}
For function with next simply replace prev() method with next(), or to minimize code duplication You may introduce third parameter and call correct method based on its value.
This method doesn't care about values of the key other but the key specified in parameter.
You may have mixed literal and numeric indexes.