How can I split a huge array into chunks? - php

Question

I am parsing about 500.000 entries into an array $properties:
$properties = array();
$handle = fopen($file_path, "r");
if ($handle) {
while (($str = fgets($handle)) !== false) {
if (strlen($str) && $str[0] == '#') {
$pdate = substr($str, 1);
$date = rtrim($pdate);
$formatted = DateTime::createFromFormat('* M d H:i:s T Y',$date);
}
$str = rtrim ($str, "\n");
$exp = explode ('=', $str);
if(count($exp) == 2){
$exp2 = explode('.', $exp[0]);
if( count($exp2) == 2 ) {
if($exp2[1] == "dateTime"){
$s = str_replace("\\","",$exp[1]);
$d = strtotime($s);
$dateTime = date('Y-m-d H:i:s', $d);
$properties [$exp2[0]][$exp2[1]] = $dateTime;
} else {
$properties [$exp2[0]][$exp2[1]] = $exp[1];
}
} else {
$properties [$exp[0]] = $exp[1];
}
}
}
fclose($handle);
} else {
echo "error";
}
This is working well so far. But I need to split the array into chunks, because otherwise the array is too big to work with it:
$properties_chunk = array_chunk($properties,10000,true);
But now I have the problem that the $properties_chunk array is not created. The system crashes. This is too much. But what can I do now?
The array should look like this in the end:
array(4) {
[0]=>
array(10000) {
["12345"]=>
array(5) {
["dateTime"]=>
string(19) "2016-10-12 19:46:25"
["fileName"]=>
string(46) "monkey.jpg"
["path"]=>
string(149) "Volumes/animals/monkey.jpg"
["size"]=>
string(7) "2650752"
}
["678790"]=>
array(5) {
["dateTime"]=>
string(19) "2016-10-12 14:39:43"
["fileName"]=>
string(45) "elephant.jpg"
["path"]=>
string(171) "Volumes/animals/elephant.jpg"
["size"]=>
string(7) "2306688"
}
... and so on.

Answer 1

If you use array_splice the items will be moved from the input array to the resulting array.
This should mean the memory use should stay the same-ish.
This will do the same as array_chunk but hopefully be less memory hungry.
$arr = [1,2,3,4,5,6,7,8,9,10];
$n = 10000;
$count = (count($arr)/$n)-1; // do not splice the last items in loop
For($i=0; $i<$count; $i++){
$res[] = array_splice($arr, 0,$n);
}
$res[] = array_splice($arr, 0,count($arr));
// here we splice the last items from arr to $res.
// Notice how we splice count($arr) instead of $n.
// If count($arr) == $n we could have done it in the loop.
// But if we assume they are not, array_splice in the loop will create empty items. This line will not.
Var_dump($res, $arr); // $res has all values, $arr is empty
https://3v4l.org/XDpdI