CampaignMonitor::createCustomField PHP Method

    public function createCustomField($name, $type = 'text', $options = array(), $listId = null)
    {
        // set list ID
        $listId = empty($listId) ? $this->getListId() : $listId;
        // check if the given type is allowed
        if (!empty($type) && !in_array($type, array('string', 'int', 'text', 'number', 'country', 'multiSelectOne', 'multiSelectMany'))) {
            // type is not allowed
            throw new CampaignMonitorException('This type is not allowed. Must be text, number, multiSelectOne or multiSelectMany.');
        }
        // if type is empty, just set it to text
        if (empty($type) || $type == 'string') {
            $type = 'text';
        }
        // catch 'int' type
        if ($type == 'int') {
            $type = 'number';
        }
        // if type is a multiple select, $options is required
        if (in_array($type, array('multiSelectOne', 'multiSelectMany')) && empty($options)) {
            // no options set
            throw new CampaignMonitorException('You need to provide an array with options for a multiSelect type.');
        }
        // set parameters
        $parameters['FieldName'] = (string) $name;
        $parameters['DataType'] = (string) ucfirst($type);
        // options found
        if (!empty($options)) {
            // set options
            $parameters['Options'] = (array) $options;
        }
        // try and create the record
        return (bool) $this->doCall('lists/' . $listId . '/customfields', $parameters, 'POST');
    }