为什么我的php foreach循环仅返回数组的最后一个值？

Question

I am currently creating a custom wordpress theme and have gotten stuck on an issue with a foreach loop. I have recreated a simple foreach loop below that represents the problem I'm having with my wordpress site.

I would expect the return value for $numbers to be 1 2 3 4, but instead when I echo $numbers, it only returns the number 4. Other answers I've found on Stack Overflow point to out of place semicolons or variable names being used twice. You can see below that this is not the case here but the value is still just the last value in the array. Can anybody explain what I should change about this code so that $numbers returns 1 2 3 4? Thanks in advance.

<?php

$my_arrays = [[1, 2],[3, 4]];
foreach($my_arrays as $array) {
  foreach($array as $a) {
    $numbers = $a . " ";
  }

}

echo $numbers;

?>

Answer 1

Use .= to append a string. Every time you were using = it was overriding the previous value, by using .= it will add it to the existing string.

<?php

$my_arrays = [[1, 2],[3, 4]];
foreach($my_arrays as $array) {
  foreach($array as $a) {
    $numbers .= $a . " "; //Use .= to append a string
  }

}

echo $numbers;

?>

Answer 2

alternative solution :

appending the array elements into an array, then implode them, this will prevent printing the empty space at the end of the text.

$my_arrays = [[1, 2],[3, 4]];
$numbers = [];
foreach($my_arrays as $array) {
  foreach($array as $a) {
    $numbers[] = $a;
  }
}
echo implode(' ', $numbers);

Answer 3

try to do this

<?php
$my_arrays = [[1, 2],[3, 4]];
foreach($my_arrays as $array) {
  foreach($array as $a) {
    $numbers .= $a . " ";
  }
}
echo $numbers;
?>