How to print or echo the array index of in PHP

Question

I'm trying to complete my assignment and this is the last thing to do now.

I know if I want to print the whole array I can just use foreach and many different method to print the entire array

foreach($v as $k=>$variable_name) { echo "<p> This is index of $k. value is $variable_name <br/></p>";}

But what if I want to only print each index separately?

I want to do the error message under each form so that is why I want each of them separate.

I tried with $v[0] and nothing appear.

is there a trick or something am I missing?

Answer 1

array_keys() will print indexes in array.

print_r(array_keys($arr));

Answer 2

If you're talking about an associative array, you need to fetch the index directly:

Example:

$array = array ('test' => 'value1', 'test2' => 'value2');   
echo $array['test']; // value1

You can do a print_r($array) to see the array structure nicely formatted:

<pre>
<?php print_r($array);?>
</pre>

What you're doing instead is fetch a value by its numerical index, like in

$array = array('test','test2','test3');
echo $array[0];  // test

On a further note, you can check beforehand if a key exists using array_key_exists():

var_dump(array_key_exists('test2',$array));  // (bool) TRUE