Using WordPress ‘get_post_custom_keys()’ PHP function

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The get_post_custom_keys() WordPress PHP function retrieves meta field names for a post.

Usage

$custom_keys = get_post_custom_keys( $post_id );

Parameters

  • $post_id (int, optional) – Post ID. Default is the ID of the global $post.

More information

See WordPress Developer Resources: get_post_custom_keys()

Examples

Retrieve and display custom field keys for a specific post

// Set the post ID
$post_id = 42;

// Get the custom field keys
$custom_keys = get_post_custom_keys($post_id);

// Display the custom field keys
if ($custom_keys) {
    foreach ($custom_keys as $key) {
        if (substr($key, 0, 1) != '_') {
            echo $key . "<br>";
        }
    }
}

Retrieve custom field keys for the current post inside the loop

// Get the custom field keys
$custom_keys = get_post_custom_keys();

// Display the custom field keys
if ($custom_keys) {
    foreach ($custom_keys as $key) {
        if (substr($key, 0, 1) != '_') {
            echo $key . "<br>";
        }
    }
}

Get custom field keys and exclude specific keys

// Get the custom field keys
$custom_keys = get_post_custom_keys();

// Exclude specific keys
$exclude_keys = array('key_to_exclude', 'another_key_to_exclude');

// Display the custom field keys
if ($custom_keys) {
    foreach ($custom_keys as $key) {
        if (!in_array($key, $exclude_keys) && substr($key, 0, 1) != '_') {
            echo $key . "<br>";
        }
    }
}

Get custom field keys and their values

// Get the custom field keys
$custom_keys = get_post_custom_keys();

// Display the custom field keys and their values
if ($custom_keys) {
    foreach ($custom_keys as $key) {
        if (substr($key, 0, 1) != '_') {
            $values = get_post_custom_values($key);
            echo $key . " => " . implode(', ', $values) . "<br>";
        }
    }
}

Count and display the number of custom fields for a post

// Get the custom field keys
$custom_keys = get_post_custom_keys();

// Count the custom fields
$count = 0;
if ($custom_keys) {
    foreach ($custom_keys as $key) {
        if (substr($key, 0, 1) != '_') {
            $count++;
        }
    }
}

// Display the number of custom fields
echo "Number of custom fields: " . $count;