PHP Merging arrays with for loops without using array_merge function

Question

I am learning more about for loops and would like to see how do you merge arrays using only for loops and not using built-in PHP functions such as array_merge().

I know you can use foreach to do this, but how would this work using only for loops and not foreach?

foreach example:

$array1 = ['judas', 'john', 'michael'];

$array2 = ['fernando', 'jsamine', 'sam', 'walter'];

$array3 = ['judas', 'john', 'mike', 'steve'];

foreach ([$array1, $array2, $array3] as $arr) {
    foreach ($arr as $values) {
        ...
    } 
}

your foreach is impossible.

Death-is-the-real-truth
– Death-is-the-real-truth

2015-05-08 22:17:23 +00:00
Commented May 8, 2015 at 22:17 — Death-is-the-real-truth
– Death-is-the-real-truth, Commented May 8, 2015 at 22:17
@anantkumarsingh why?

Don't Panic
– Don't Panic

2015-05-08 22:54:35 +00:00
Commented May 8, 2015 at 22:54 — Don't Panic
– Don't Panic, Commented May 8, 2015 at 22:54
foreach didn't work in this manner.

Death-is-the-real-truth
– Death-is-the-real-truth

2015-05-08 23:02:55 +00:00
Commented May 8, 2015 at 23:02 — Death-is-the-real-truth
– Death-is-the-real-truth, Commented May 8, 2015 at 23:02

Don't Panic · Accepted Answer · 2015-05-08 22:48:51Z

1

Yes, you can do this using just for loops.

$array1 = ['judas', 'john', 'michael'];    
$array2 = ['fernando', 'jsamine', 'sam', 'walter'];
$array3 = ['judas', 'john', 'mike', 'steve'];

$all_arrays = [$array1, $array2, $array3];
$merged = [];
for ($i = 0; $i < 3; $i++) {
    $arr = $all_arrays[$i];
    $x = count($arr);
    for ($j=0; $j < $x; $j++) { 
        // Using the value as the key in the merged array ensures 
        // that you will end up with distinct values.
       $merged[$arr[$j]] = 1;
    }
}

// You could use array_keys() to do get the final result, but if you
// want to use just loops then it would work like this:
$final = [];
$x = count($merged);
for ($i=0; $i < $x; $i++) { 
  $final[] = key($merged);
  next($merged);
}

var_dump($final);

key() and next() ARE php functions. But I really do not know of a way to get to the keys without using either foreach or some php function.

edited May 8, 2015 at 22:48

answered May 8, 2015 at 22:24

Don't Panic

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8 Comments

cattywampus Over a year ago

I'm looking to do this with for loops not foreach.

Don't Panic Over a year ago

Oops, I totally missed that part of the question. :( It's still possible. I will edit.

Don't Panic Over a year ago

@cattywampus for loops. I saw another question from you the other day that was similar to this. I'm curious what your interest is in using for loops rather than foreach.

cattywampus Over a year ago

Just trying to get an understanding on how to use for loops in different situations. In other words for practice.

Don't Panic Over a year ago

That's cool. I was just wondering. You probably know this, but usually a for loop is used in cases when you have a set number of times you need to do something. Using them to iterate arrays is generally going to be more cumbersome than foreach, especially if you need to access the keys.

|

Sasha · Accepted Answer · 2018-05-17 13:15:28Z

1

function arrayMerge(array $arrays) {
    $mergeArray = [];

    foreach ($arrays as  $key => $array) {
        foreach($array as $finalArray) {
            $mergeArray[] = $finalArray;
        }
    }

   return $mergeArray;
}


$array1 = [
    'Laravel', 'Codeigniter', 'Zend'
];

$array2 = [
    'Node js', 'Vue js', 'Angular js'
];

$array3 = [
    'Python', 'Django', 'Ruby'
];

print_r(arrayMerge([$array1, $array2, $array3]));

edited May 17, 2018 at 13:15

Sasha

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answered May 17, 2018 at 10:40

shailesh yadav

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Comments

Richard · Accepted Answer · 2015-05-08 22:19:42Z

0

Iterate each array on its own:

foreach($array2 as $v)
  if(!in_array($v, $array1))
    $array1[] = $v;
foreach($array3 as $v)
  if(!in_array($v, $array1))
    $array1[] = $v;

Or simply use array_merge() - there is no reason for do not do it.

answered May 8, 2015 at 22:19

Richard

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1 Comment

cattywampus Over a year ago

Can this be doing using for loops? Not foreach

Monu Kumar · Accepted Answer · 2017-11-04 10:03:12Z

0

$a=array('1','2','3','4','5');
$b=array('a','b','c','d','e');
$c=count($b);
      for($i=0; $i<$c; $i++) 
          {
             $a[]=$b[$i];  // each element  1 by 1 store inside the array $a[]
          }
print_r($a);

edited Nov 4, 2017 at 10:03

answered Nov 4, 2017 at 9:38

Monu Kumar

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2 Comments

yuantonito Over a year ago

You need to pay attention to your code format in order for people to read easily your code.

mickmackusa Over a year ago

The sample data in this under-explained answer does not resemble the asker's sample data / scenario.

Diwakar Kumar Keshri · Accepted Answer · 2021-06-03 14:01:13Z

0

$arr1 = array(1,2,3,4,5);
$arr2 = array(2,5,6,7,8);
$allval = array();
foreach($arr2 as $key=>$val){
    $arr1[] = $val;
}
foreach($arr1 as $k=>$v){
    if(!in_array($v,$allval)){
        $allval[] = $v;
    }
}
echo "<pre>"; print_R($allval);

answered Jun 3, 2021 at 14:01

Diwakar Kumar Keshri

12 bronze badges

1 Comment

mickmackusa Over a year ago

The sample data in this unexplained answer does not resemble the asker's sample data / scenario.

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