copy data from text file to php array

Option 1: If id is always the first line of the group, you can do a simpler approach using just 1 loop.

Using array_values will convert associative array into simple array.

$fh = fopen('newfile.txt','r');
$result = array();
while ($line = fgets($fh)) {
    $line = trim($line);
    if ( $line !== '' ) {
        $line = explode(":", $line, 2);
        if ( trim( $line[0] ) === 'id' ) $id = trim( $line[1] );
        $result[$id][trim( $line[0] )] = trim( $line[1] );
    }
}
fclose($fh);

echo "<pre>";
print_r( array_values($result) );
echo "</pre>";

Option 2: You can use loop thru each line of the file. Chunk the array. And use array_reduce to format the array.

$fh = fopen('newfile.txt','r');                                //Open file
$arr = array();
while ($line = fgets($fh)) {                                   //Loop thru each line
    $arr[] = trim($line);                                      //Trim the line and push in array
}
fclose($fh);

$arr = array_chunk( $arr, 4 );                                  //chunk array in the size of 4

//use array_reduce to format the array Format array
$result = array_reduce($arr, function($c,$v){
    $temp = array();
    $id = "";

    foreach($v as $val) {
        $val = explode(":", $val, 2);
        $temp[ trim( $val[0] ) ] = trim( $val[1] );
    }

    $c[$id] = $temp;
    return $c;
},array());

echo "<pre>";
print_r( $result );
echo "</pre>";

This will result to:

Array
(
    [24153] => Array
        (
            [firstname] => john
            [lastname] => smith
            [registered] => true
        )

    [27663] => Array
        (
            [firstname] => ben
            [lastname] => jackson
            [registered] => false
        )

)

Please use this code. This is tested code and working properly as you required. In this script, there is no extra loop required. We are achieved just by the use of if and else.

<?php
if ($file = fopen("file.txt", "r")) {
        $dataArray = array();
        $newline = '';
        $id = '';
    while(!feof($file)) {
        $line = fgets($file);
        # do same stuff with the $line
        if (strpos($line, "id:") !== false) {
            //print_r($line);echo '</br>';
            $id_line = explode(":",$line);
            $id = $id_line[1];
        }else{
            if(!empty($id)){
                $new_line = explode(":",$line);
                $dataArray[$id][$new_line[0]] = $new_line[1];
            }
        }



    }
    fclose($file);
}
echo '<pre>';
print_r($dataArray);
?>

Output:

Array
(
    [ 24153] => Array
        (
            [firstname] =>  john

            [lastname] =>  smith

            [registered] =>  true

        )

    [ 27663] => Array
        (
            [firstname] =>  ben

            [lastname] =>  jackson

            [registered] =>  false
        )

)

I will rather do using array_map and array_filter to minimise loop. I have tried with simple string manipulation , you can do it using fopen.

Explanations are included in comments below

$str="id: 24153
firstname: john
lastname: smith
registered: true
id: 27663
firstname: ben
lastname: jackson
registered: false";
//explode by new line
$arr=explode("\n",$str);
//take the value only,OP is saying format is same
$arr1=array_map(function ($a) { return str_replace(":","",strstr($a, ':')); }, $arr);
//remap the value if index is divisible by 4 , that is if it is id, remember the format is fixed
$arr2=array_values(array_filter(array_map(function ($a,$k)use($arr1) { if($k%4==0) { return array($a=>array('firstname'=>$arr1[$k+1],'last_name'=>$arr1[$k+2],'registered'=>$arr1[$k+3]));} else {return null;} }, $arr1,array_keys($arr1))));
echo "<pre>";
print_r($arr2);

output

Array
(
    [0] => Array
        (
            [ 24153] => Array
                (
                    [firstname] =>  john
                    [last_name] =>  smith
                    [registered] =>  true
                )

        )

    [1] => Array
        (
            [ 27663] => Array
                (
                    [firstname] =>  ben
                    [last_name] =>  jackson
                    [registered] =>  false
                )

        )

)

working fiddle: http://phpfiddle.org/main/code/6n5g-bvpx