Get field key by field name

• LeffDesign

• August 21, 2013 at 11:20 pm

Hi Elliot,

Sorry, I did ask this question before and thought I had the solution. However I’m still searching for the answer.

Let’s say I only have a field name ($field_name), how can I get the field key only from this variable. So not related to a post id or something else.

Tried several things but cannot find the right ‘get’ query.

Thanks!

• wells5609

• August 22, 2013 at 11:10 am

The “real” answer: go to the Field Group admin page, click the “display field key” button in help dropdown, then copy & paste the key into code.

Maybe closer to the answer you’re looking for:

 function acf_field_key($field_name, $post_id = false){
	
	if ( $post_id )
		return get_field_reference($field_name, $post_id);
	
	if( !empty($GLOBALS['acf_register_field_group']) ) {
		
		foreach( $GLOBALS['acf_register_field_group'] as $acf ) :
			
			foreach($acf['fields'] as $field) :
				
				if ( $field_name === $field['name'] )
					return $field['key'];
			
			endforeach;
			
		endforeach;
	}
        return $field_name;
}

However, this only works for fields registered with PHP via register_field_group().

• MisterBlack

• August 25, 2016 at 3:12 am

Hi,

I’ve been struggling with this for some time, and this is my solution, I guess it’s not perfect, but is working for me.

function get_acf_field_keys( $custom_field_slug = '' ) {

		$result = array();

		$meta_key_start = 'field_';

		$acf_args = array(
			'post_type'		=> 'acf'
		);

		if ( $custom_field_slug !== '' ) {
			$acf_args[ 'name' ] = $custom_field_slug;
		}

		$acf_query = new WP_Query( $acf_args );

		if ( $acf_query->have_posts() ) {

			while ( $acf_query->have_posts() ) {

				$acf_query->the_post();

				$meta_values = get_post_meta( get_the_id() );

				foreach ( $meta_values as $meta_key => $meta_value ) {
					
					if ( substr( $meta_key, 0, strlen( $meta_key_start ) ) === $meta_key_start ) {

						$meta_value_array = unserialize( $meta_value[0] );

						$result[ $meta_value_array['name'] ] = $meta_key;

					}

				}

			}

		}

		wp_reset_postdata();

		if ( empty( $result ) ) {
			$result = false;
		}

		return $result;

	}

Basically, I’m using WP_Query to iterate through acf posts (Custom fields) & get the metadata, then filter the metadata starting with ‘field_’ to fill an array using the field name as key and the field key as value, to be used like this:

if ( $field_keys = get_acf_field_keys( 'acf_sample-custom-field' ) ) {

		if ( isset( $field_keys[ 'sample_field_name' ] ) ) {
			$sample_field_key = $field_keys[ 'sample_field_name' ];
		}
}

I hope this is helpful for someone.

• designerstudio

• August 4, 2017 at 4:29 am

Hi,

I found a perfect solution: https://gist.github.com/mcguffin/81509c36a4a28d9c682e

• almbay

• September 20, 2017 at 11:23 pm

There is a much easier solution given that the field exists on a given post, which you already seems to assume with your current code.

$field = get_field_object('listing_type');
$field_key = $field['key'];

Done.

• ethernek

• April 17, 2018 at 12:41 am

Thank you very much! I did a slight modification in order to be able to retrieve the name or the field key depending what is given, because I needed the exact opposite. I paste it here for future reference to others. Cheers!

function acf_get_field_info( $return = 'name', $field_key, $post_id ) {
		global $wpdb;
		//choose name 
		if($return == 'name'){
			$acf_fields = $wpdb->get_results( $wpdb->prepare( "SELECT ID,post_parent,post_excerpt FROM $wpdb->posts WHERE post_name=%s AND post_type=%s" , $field_key , 'acf-field' ) );
		}elseif($return == 'key'){
			$acf_fields = $wpdb->get_results( $wpdb->prepare( "SELECT ID,post_parent,post_name FROM $wpdb->posts WHERE post_excerpt=%s AND post_type=%s" , $field_key , 'acf-field' ) );
		}
		// get all fields with that name.
		switch ( count( $acf_fields ) ) {
			case 0: // no such field
				return false;
			case 1: // just one result.
				return $acf_fields[0]->post_excerpt;
		}
		// result is ambiguous
		// get IDs of all field groups for this post
		$field_groups_ids = array();
		$field_groups = acf_get_field_groups( array(
			'post_id' => $post_id,
		) );
		foreach ( $field_groups as $field_group )
			$field_groups_ids[] = $field_group['ID'];

		// Check if field is part of one of the field groups
		// Return the first one.
		foreach ( $acf_fields as $acf_field ) {
			if ( in_array($acf_field->post_parent,$field_groups_ids) )
				return $acf_field->post_name;
		}
		return false;
	}

• Dave Navarro, Jr.

• April 18, 2018 at 12:15 am

So, the issue I have is that get_field_object() returns an empty value when creating a new post.

Also, none of these solutions work correctly if you have the same slug in multiple field collections for different post types.

Really wish ACF has a get_field_info( $post_type, $post_slug );

• krolyn

• April 10, 2020 at 7:41 pm

Why can’t you simply use —

$field = acf_get_field( $field_name );
$field_key = $field['key'];