php foreach loop

Question

I have two arrays in my code. Need to perform a foreach loop on both of these arrays at one time. Is it possible to supply two arguments at the same time such as foreach($array1 as $data1 and $array2 as $data2) or something else?

• Cyclonecode: Why do you need to loop both arrays at the same time?
• jprofitt: Will they have the same number of elements?

Answer 1

If they both the same keys, you can do this:

foreach($array1 as $key=>data1){
 $data2 = $array2[$key];
}

Answer 2

Assuming both have the same number of elements

If they both are 0-indexed arrays:

foreach ($array_1 as $key => $data_1) {
 $data_2 = $array_2[$key];
}

Otherwise:

$keys = array_combine(array_keys($array_1), array_keys($array_2));
foreach ($keys as $key_1 => $key_2) {
 $data_1 = $array_1[$key_1];
 $data_2 = $array_2[$key_2];
}

• capi: nice solution with the keys mapping, +1

Answer 3

Dont use a foreach. use a For, and use the incremented index, eg. $i++ to access both arrays at once.

Are both arrays the same size always? Then this will work:

$max =sizeof($array);
for($i = 0; $i < $max; $i++)
array[$i].attribute
array2[$i].attribute

If the arrays are different sizes, you may have to tweak your approach. Possibly use a while.

iterative methods:

http://php.net/manual/en/control-structures.while.php

http://php.net/manual/en/control-structures.for.php

http://php.net/manual/en/control-structures.do.while.php

• capi: never use a function inside a for condition, it will execute it each loop, your example should be instead : for ($i = 0, $max = sizeof($array); $i < $max; $i++)
• martinstoeckli: That's what the for loop is for. I would add the {...}, so one can see that you access the arrays from inside the loop.

Answer 4

use for or while loop e.g.

$i = 0; 
while($i < count($ar1) && $i < count($ar2) ) // $i less than both length ! 
{ 
 $ar1Item = $ar1[$i];
 $ar2Item = $ar2[$i];
 $i++;
}

• capi: if you're using a while loop, define the counts beforehand as variables, no need to do the count each loop (same as the post below), use while ($i<$max1 && $i<$max2) and define $max1 = count($ar1) and same for ar2 before the while loop

Answer 5

No to my knowledge with foreach, but can be easily done with for:

<?php
$cond1 = 0<count($array1);
$cond2 = 0<count($array2);
for ($i=0;$cond1 || $cond2;$i++)
{
 if ($cond1)
 {
 // work with $array1
 }
 if ($cond2)
 {
 // work with $array2
 }
 $cond1 = 0<count($array1);
 $cond2 = 0<count($array2);
}
?>