PHP Array iteration Using an incremental index
Example
This method works by incrementing an integer from 0 to the greatest index in the array.
$colors = ['red', 'yellow', 'blue', 'green'];
for ($i = 0; $i < count($colors); $i++) {
echo 'I am the color ' . $colors[$i] . '<br>';
}
This also allows iterating an array in reverse order without using array_reverse, which may result in overhead if the array is large.
$colors = ['red', 'yellow', 'blue', 'green'];
for ($i = count($colors) - 1; $i >= 0; $i--) {
echo 'I am the color ' . $colors[$i] . '<br>';
}
You can skip or rewind the index easily using this method.
$array = ["alpha", "beta", "gamma", "delta", "epsilon"];
for ($i = 0; $i < count($array); $i++) {
echo $array[$i], PHP_EOL;
if ($array[$i] === "gamma") {
$array[$i] = "zeta";
$i -= 2;
} elseif ($array[$i] === "zeta") {
$i++;
}
}
Output:
alpha
beta
gamma
beta
zeta
epsilon
For arrays that do not have incremental indices (including arrays with indices in reverse order, e.g. [1 => "foo", 0 => "bar"], ["foo" => "f", "bar" => "b"]), this cannot be done directly. array_values or array_keys can be used instead:
$array = ["a" => "alpha", "b" => "beta", "c" => "gamma", "d" => "delta"];
$keys = array_keys($array);
for ($i = 0; $i < count($array); $i++) {
$key = $keys[$i];
$value = $array[$key];
echo "$value is $key\n";
}
