Gravity Forms | Check For Duplicate Values Between a Set of Fields

gw-check-for-duplicate-values-between-a-set-of-fields.php

<?php
/**
 * Gravity Wiz // Gravity Forms // Check For Duplicate Values Between a Set of Fields
 * https://gravitywiz.com/
 *
 * Checks for duplicate values between a set of fields. Can be used to create a manual "rank these" setup
 * using dropdown fields.
 * 
 * Instructions:
 * Update "123" to your form ID, "4" to the field ID of the last field that you want to check for duplicate values, 
 * and "5, 6, 7, 8" to the IDs of the rest of the fields you want to check for duplicate values.
 * 
 */
  
 add_filter( 'gform_field_validation_123_4', function( $result, $value, $form ) {

    $other_field_ids = array( 5, 6, 7, 8 );
    
    $last_field = $value;
    $field_values = array( $last_field );
    foreach( $other_field_ids as $field_id ) {
        array_push( $field_values, rgpost( 'input_' . $field_id ) );
    }

    $double_found = false;
    foreach( $field_values as $field_value_x ) {
        $doubles_count = 0; // If becomes more than 1 (finding itself), then an entry was submitted twice
        foreach( $field_values as $field_value_y ) {
            if( $field_value_x == $field_value_y ) {
                $doubles_count++;
            }
        }
        if( $doubles_count > 1 ) {
            $double_found = true;
        }
    }
    
    if ( $result['is_valid'] && $double_found ) {
        $result['is_valid'] = false;
        $result['message']  = 'Some options were ranked multiple times. Please try again.'; // Can edit this message to your preference.
    }

	return $result;
}, 10, 4 );