Question

I was writing a simple PHP page and a few foreach loops were used.

Here are the scripts:

$arrs = array("a", "b", "c");

foreach ($arrs as $arr) {
    if(substr($arr,0,1)=="b") {
        echo "This is b";
    }     
} // End of first 'foreach' loop, and I didn't use 'ifelse' here.

And when this foreach ends, I wrote another foreach loop in which all the values in the foreach loop was the same as in the previous foreach.

foreach ($arrs as $arr) {
    if(substr($arr,0,1)=="c") {
        echo "This is c";
    }     
}

I am not sure if it is a good practice to have two foreach loops with the same values and keys.

Will the values get overwritten in the first foreach loop?

Answer 1

It’s OK until you start using references and then you can get strange behaviour, for example:

<?php
$array = array(1,2,3,4);
//notice reference &
foreach ($array as & $item) {   }

$array2 = array(10, 11, 12, 13);
foreach ($array2 as $item) {   }

print_r($array);

Outputs this:

Array
(
    [0] => 1
    [1] => 2
    [2] => 3
    [3] => 13
)

Because the first foreach leaves $item as a reference to $array[3], $array[3] is sequentially set to each value in $array2.

You can solve this be doing unset($item) after the first foreach, which will remove the reference, but this isn’t actually an issue in your case, as you are not using references with foreach.