php数组将密钥从foreach循环存储到字符串中

Question

I have a key-pair array like this

$option['33']="Steak Doness";
$option['34']="Size";
$option['35']="Cooking Method";

I want to store the keys into a string like this

$key="33,34,35,";

I try to use foreach loop

$key="";

foreach($option as $key => $value) {
    $key=$key.",";
}
echo $key;

However, my output is

35,

May i know which part went wrong?

Answer 1

You miss use the $key in your script.

The problem is with the $key which is in the foreach loop... . In each time your $key variable updated with the loop... Try with difference variable in your script.

OR, simply use

echo $key = implode(",", array_keys($option));

Answer 2

1st change your varible $key to $keys replace one line

$key=$key.",";

to

$keys .= $key . ",";

it will work 100%