Retrieving data from multiple arrays using a while loop

Question

I'm looking for a way to optimize the following code using while loop.. I've got 4 arrays and would like to pull the 1st value from each array in the most efficient way. This is the original code which works fine:

$arr1 = array ("55", "66", "77");
$arr2 = array ("54", "64", "771");
$arr3 = array ("53", "62", "772");
$arr4 = array ("52", "60", "773");
$x = 1;
$result = "null";

echo $arr1[0] . " | " ; 
echo $arr2[0]. " | " ; 
echo $arr3[0]. " | " ; 
echo $arr4[0]. " | " ;

Blow is my attempt to optimize it but it doesn't seems to be working:

$arr1 = array ("55", "66", "77");
$arr2 = array ("54", "64", "771");
$arr3 = array ("53", "62", "772");
$arr4 = array ("52", "60", "773");
$x = 1;
$result = "null";

while($x < 5) {
$result = "$arr".$x."[0]";
echo $result;
echo " | ";
$x = $x +1;
}

The output I'm getting is 1[1] | 2[1] | 3[1] | 4[1]
Instead of 55 | 54 | 53 | 52 |

Thank you all!

JustBaron · Accepted Answer · 2016-12-22 14:34:02Z

4

while($x < 5) {
    $result = ${"arr".$x}[0];
    echo $result;
    echo " | ";
    $x++;
}

or a neater solution:

$arr1 = array ("55", "66", "77");
$arr2 = array ("54", "64", "771");
$arr3 = array ("53", "62", "772");
$arr4 = array ("52", "60", "773");

for($x=1; $x<5; $x++) {
    $result = ${"arr".$x}[0];
    echo $result." | ";
}

edited Dec 22, 2016 at 14:34

answered Dec 22, 2016 at 14:25

JustBaron

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1 Comment

mtizziani Over a year ago

${"arr" . $x}is the correct answer to call a automatic generated variable name. look at the example above

RomanPerekhrest · Accepted Answer · 2016-12-22 14:31:50Z

1

"One-line" solution using call_user_func_array and array_column functions:

$result = implode(" | ", call_user_func_array('array_column', [[$arr1, $arr2, $arr3, $arr4], 0]));

print_r($result);

The output:

55 | 54 | 53 | 52

edited Dec 22, 2016 at 14:31

answered Dec 22, 2016 at 14:26

RomanPerekhrest

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