static $builders = [           ‘NOT‘ => ‘buildNotCondition‘,           ‘AND‘ => ‘buildAndCondition‘,           ‘OR‘ => ‘buildOrCondition‘,           ‘BETWEEN‘ => ‘buildBetweenCondition‘,           ‘NOT BETWEEN‘ => ‘buildBetweenCondition‘,           ‘IN‘ => ‘buildInCondition‘,           ‘NOT IN‘ => ‘buildInCondition‘,           ‘REGEX‘ => ‘buildRegexCondition‘,           ‘LIKE‘ => ‘buildLikeCondition‘,                   ];

public function buildGtCondition($operator, $operands){    if (!isset($operands[0], $operands[1])) {        throw new InvalidParamException("Operator ‘$operator‘ requires two operands.");    }    list($column, $value) = $operands;    return [$column => [‘?gt‘ => $value]];}  public function buildGteCondition($operator, $operands){    if (!isset($operands[0], $operands[1])) {        throw new InvalidParamException("Operator ‘$operator‘ requires two operands.");    }    list($column, $value) = $operands;    return [$column => [‘?gte‘ => $value]];}  public function buildLtCondition($operator, $operands){    if (!isset($operands[0], $operands[1])) {        throw new InvalidParamException("Operator ‘$operator‘ requires two operands.");    }    list($column, $value) = $operands;    return [$column => [‘?lt‘ => $value]];} public function buildLteCondition($operator, $operands){    if (!isset($operands[0], $operands[1])) {        throw new InvalidParamException("Operator ‘$operator‘ requires two operands.");    }    list($column, $value) = $operands;    return [$column => [‘?lte‘ => $value]];}

public function buildCondition($condition)   {       static $builders = [           ‘NOT‘ => ‘buildNotCondition‘,           ‘AND‘ => ‘buildAndCondition‘,           ‘OR‘ => ‘buildOrCondition‘,           ‘BETWEEN‘ => ‘buildBetweenCondition‘,           ‘NOT BETWEEN‘ => ‘buildBetweenCondition‘,           ‘IN‘ => ‘buildInCondition‘,           ‘NOT IN‘ => ‘buildInCondition‘,           ‘REGEX‘ => ‘buildRegexCondition‘,           ‘LIKE‘ => ‘buildLikeCondition‘,           ‘>‘  => ‘buildGtCondition‘,           ‘>=‘ => ‘buildGteCondition‘,           ‘<‘  => ‘buildLtCondition‘,           ‘<=‘     => ‘buildLteCondition‘,       ];

mongodb->getCollection(‘customer‘); * $collection->insert([‘name‘ => ‘John Smith‘, ‘status‘ => 1]); * ~~~ * * To perform "find" queries, please use [[Query]] instead. * * Mongo uses JSON format to specify query conditions with quite specific syntax. * However Collection class provides the ability of "translating" common condition format used "yii\db\*" * into Mongo condition. * For example: * ~~~ * $condition = [ *     [ *         ‘OR‘, *         [‘AND‘, [‘first_name‘ => ‘John‘], [‘last_name‘ => ‘Smith‘]], *         [‘status‘ => [1, 2, 3]] *     ], * ]; * print_r($collection->buildCondition($condition)); * // outputs : * [ *     ‘$or‘ => [ *         [ *             ‘first_name‘ => ‘John‘, *             ‘last_name‘ => ‘John‘, *         ], *         [ *             ‘status‘ => [‘$in‘ => [1, 2, 3]], *         ] *     ] * ] * ~~~ * * Note: condition values for the key ‘_id‘ will be automatically cast to [[\MongoId]] instance, * even if they are plain strings. However, if you have other columns, containing [[\MongoId]], you * should take care of possible typecast on your own. * * @property string $fullName Full name of this collection, including database name. This property is * read-only. * @property array $lastError Last error information. This property is read-only. * @property string $name Name of this collection. This property is read-only. * * @author Paul Klimov <klimov.paul@gmail.com> * @since 2.0 */class Collection extends Object{    /**     * @var \MongoCollection Mongo collection instance.     */    public $mongoCollection;      /**     * @return string name of this collection.     */    public function getName()    {        return $this->mongoCollection->getName();    }     /**     * @return string full name of this collection, including database name.     */    public function getFullName()    {        return $this->mongoCollection->__toString();    }     /**     * @return array last error information.     */    public function getLastError()    {        return $this->mongoCollection->db->lastError();    }     /**     * Composes log/profile token.     * @param string $command command name     * @param array $arguments command arguments.     * @return string token.     */    protected function composeLogToken($command, $arguments = [])    {        $parts = [];        foreach ($arguments as $argument) {            $parts[] = is_scalar($argument) ? $argument : $this->encodeLogData($argument);        }         return $this->getFullName() . ‘.‘ . $command . ‘(‘ . implode(‘, ‘, $parts) . ‘)‘;    }     /**     * Encodes complex log data into JSON format string.     * @param mixed $data raw data.     * @return string encoded data string.     */    protected function encodeLogData($data)    {        return json_encode($this->processLogData($data));    }     /**     * Pre-processes the log data before sending it to `json_encode()`.     * @param mixed $data raw data.     * @return mixed the processed data.     */    protected function processLogData($data)    {        if (is_object($data)) {            if ($data instanceof \MongoId ||                $data instanceof \MongoRegex ||                $data instanceof \MongoDate ||                $data instanceof \MongoInt32 ||                $data instanceof \MongoInt64 ||                $data instanceof \MongoTimestamp            ) {                $data = http://www.mamicode.com/get_class($data) . ‘(‘ . $data->__toString() . ‘)‘;"find" queries use [[Query]] class.     * @param array $condition query condition     * @param array $fields fields to be selected     * @return \MongoCursor cursor for the search results     * @see Query     */    public function find($condition = [], $fields = [])    {        return $this->mongoCollection->find($this->buildCondition($condition), $fields);    }     /**     * Returns a single document.     * @param array $condition query condition     * @param array $fields fields to be selected     * @return array|null the single document. Null is returned if the query results in nothing.     * @see http://www.php.net/manual/en/mongocollection.findone.php     */    public function findOne($condition = [], $fields = [])    {        return $this->mongoCollection->findOne($this->buildCondition($condition), $fields);    }     /**     * Updates a document and returns it.     * @param array $condition query condition     * @param array $update update criteria     * @param array $fields fields to be returned     * @param array $options list of options in format: optionName => optionValue.     * @return array|null the original document, or the modified document when $options[‘new‘] is set.     * @throws Exception on failure.     * @see http://www.php.net/manual/en/mongocollection.findandmodify.php     */    public function findAndModify($condition, $update, $fields = [], $options = [])    {        $condition = $this->buildCondition($condition);        $token = $this->composeLogToken(‘findAndModify‘, [$condition, $update, $fields, $options]);        Yii::info($token, __METHOD__);        try {            Yii::beginProfile($token, __METHOD__);            $result = $this->mongoCollection->findAndModify($condition, $update, $fields, $options);            Yii::endProfile($token, __METHOD__);             return $result;        } catch (\Exception $e) {            Yii::endProfile($token, __METHOD__);            throw new Exception($e->getMessage(), (int) $e->getCode(), $e);        }    }     /**     * Inserts new data into collection.     * @param array|object $data data to be inserted.     * @param array $options list of options in format: optionName => optionValue.     * @return \MongoId new record id instance.     * @throws Exception on failure.     */    public function insert($data, $options = [])    {        $token = $this->composeLogToken(‘insert‘, [$data]);        Yii::info($token, __METHOD__);        try {            Yii::beginProfile($token, __METHOD__);            $options = array_merge([‘w‘ => 1], $options);            $this->tryResultError($this->mongoCollection->insert($data, $options));            Yii::endProfile($token, __METHOD__);             return is_array($data) ? $data[‘_id‘] : $data->_id;        } catch (\Exception $e) {            Yii::endProfile($token, __METHOD__);            throw new Exception($e->getMessage(), (int) $e->getCode(), $e);        }    }     /**     * Inserts several new rows into collection.     * @param array $rows array of arrays or objects to be inserted.     * @param array $options list of options in format: optionName => optionValue.     * @return array inserted data, each row will have "_id" key assigned to it.     * @throws Exception on failure.     */    public function batchInsert($rows, $options = [])    {        $token = $this->composeLogToken(‘batchInsert‘, [$rows]);        Yii::info($token, __METHOD__);        try {            Yii::beginProfile($token, __METHOD__);            $options = array_merge([‘w‘ => 1], $options);            $this->tryResultError($this->mongoCollection->batchInsert($rows, $options));            Yii::endProfile($token, __METHOD__);             return $rows;        } catch (\Exception $e) {            Yii::endProfile($token, __METHOD__);            throw new Exception($e->getMessage(), (int) $e->getCode(), $e);        }    }     /**     * Updates the rows, which matches given criteria by given data.     * Note: for "multiple" mode Mongo requires explicit strategy "$set" or "$inc"     * to be specified for the "newData". If no strategy is passed "$set" will be used.     * @param array $condition description of the objects to update.     * @param array $newData the object with which to update the matching records.     * @param array $options list of options in format: optionName => optionValue.     * @return integer|boolean number of updated documents or whether operation was successful.     * @throws Exception on failure.     */    public function update($condition, $newData, $options = [])    {        $condition = $this->buildCondition($condition);        $options = array_merge([‘w‘ => 1, ‘multiple‘ => true], $options);        if ($options[‘multiple‘]) {            $keys = array_keys($newData);            if (!empty($keys) && strncmp(‘$‘, $keys[0], 1) !== 0) {                $newData = http://www.mamicode.com/[‘$set‘ => $newData];"false" on failure.     * @throws Exception on failure.     */    public function distinct($column, $condition = [])    {        $condition = $this->buildCondition($condition);        $token = $this->composeLogToken(‘distinct‘, [$column, $condition]);        Yii::info($token, __METHOD__);        try {            Yii::beginProfile($token, __METHOD__);            $result = $this->mongoCollection->distinct($column, $condition);            Yii::endProfile($token, __METHOD__);             return $result;        } catch (\Exception $e) {            Yii::endProfile($token, __METHOD__);            throw new Exception($e->getMessage(), (int) $e->getCode(), $e);        }    }     /**     * Performs aggregation using Mongo Aggregation Framework.     * @param array $pipeline list of pipeline operators, or just the first operator     * @param array $pipelineOperator additional pipeline operator. You can specify additional     * pipelines via third argument, fourth argument etc.     * @return array the result of the aggregation.     * @throws Exception on failure.     * @see http://docs.mongodb.org/manual/applications/aggregation/     */    public function aggregate($pipeline, $pipelineOperator = [])    {        $args = func_get_args();        $token = $this->composeLogToken(‘aggregate‘, $args);        Yii::info($token, __METHOD__);        try {            Yii::beginProfile($token, __METHOD__);            $result = call_user_func_array([$this->mongoCollection, ‘aggregate‘], $args);            $this->tryResultError($result);            Yii::endProfile($token, __METHOD__);             return $result[‘result‘];        } catch (\Exception $e) {            Yii::endProfile($token, __METHOD__);            throw new Exception($e->getMessage(), (int) $e->getCode(), $e);        }    }     /**     * Performs aggregation using Mongo "group" command.     * @param mixed $keys fields to group by. If an array or non-code object is passed,     * it will be the key used to group results. If instance of [[\MongoCode]] passed,     * it will be treated as a function that returns the key to group by.     * @param array $initial Initial value of the aggregation counter object.     * @param \MongoCode|string $reduce function that takes two arguments (the current     * document and the aggregation to this point) and does the aggregation.     * Argument will be automatically cast to [[\MongoCode]].     * @param array $options optional parameters to the group command. Valid options include:     *  - condition - criteria for including a document in the aggregation.     *  - finalize - function called once per unique key that takes the final output of the reduce function.     * @return array the result of the aggregation.     * @throws Exception on failure.     * @see http://docs.mongodb.org/manual/reference/command/group/     */    public function group($keys, $initial, $reduce, $options = [])    {        if (!($reduce instanceof \MongoCode)) {            $reduce = new \MongoCode((string) $reduce);        }        if (array_key_exists(‘condition‘, $options)) {            $options[‘condition‘] = $this->buildCondition($options[‘condition‘]);        }        if (array_key_exists(‘finalize‘, $options)) {            if (!($options[‘finalize‘] instanceof \MongoCode)) {                $options[‘finalize‘] = new \MongoCode((string) $options[‘finalize‘]);            }        }        $token = $this->composeLogToken(‘group‘, [$keys, $initial, $reduce, $options]);        Yii::info($token, __METHOD__);        try {            Yii::beginProfile($token, __METHOD__);            // Avoid possible E_DEPRECATED for $options:            if (empty($options)) {                $result = $this->mongoCollection->group($keys, $initial, $reduce);            } else {                $result = $this->mongoCollection->group($keys, $initial, $reduce, $options);            }            $this->tryResultError($result);             Yii::endProfile($token, __METHOD__);            if (array_key_exists(‘retval‘, $result)) {                return $result[‘retval‘];            } else {                return [];            }        } catch (\Exception $e) {            Yii::endProfile($token, __METHOD__);            throw new Exception($e->getMessage(), (int) $e->getCode(), $e);        }    }     /**     * Performs aggregation using Mongo "map reduce" mechanism.     * Note: this function will not return the aggregation result, instead it will     * write it inside the another Mongo collection specified by "out" parameter.     * For example:     *     * ~~~     * $customerCollection = Yii::$app->mongo->getCollection(‘customer‘);     * $resultCollectionName = $customerCollection->mapReduce(     *     ‘function () {emit(this.status, this.amount)}‘,     *     ‘function (key, values) {return Array.sum(values)}‘,     *     ‘mapReduceOut‘,     *     [‘status‘ => 3]     * );     * $query = new Query();     * $results = $query->from($resultCollectionName)->all();     * ~~~     *     * @param \MongoCode|string $map function, which emits map data from collection.     * Argument will be automatically cast to [[\MongoCode]].     * @param \MongoCode|string $reduce function that takes two arguments (the map key     * and the map values) and does the aggregation.     * Argument will be automatically cast to [[\MongoCode]].     * @param string|array $out output collection name. It could be a string for simple output     * (‘outputCollection‘), or an array for parametrized output ([‘merge‘ => ‘outputCollection‘]).     * You can pass [‘inline‘ => true] to fetch the result at once without temporary collection usage.     * @param array $condition criteria for including a document in the aggregation.     * @param array $options additional optional parameters to the mapReduce command. Valid options include:     *  - sort - array - key to sort the input documents. The sort key must be in an existing index for this collection.     *  - limit - the maximum number of documents to return in the collection.     *  - finalize - function, which follows the reduce method and modifies the output.     *  - scope - array - specifies global variables that are accessible in the map, reduce and finalize functions.     *  - jsMode - boolean -Specifies whether to convert intermediate data into BSON format between the execution of the map and reduce functions.     *  - verbose - boolean - specifies whether to include the timing information in the result information.     * @return string|array the map reduce output collection name or output results.     * @throws Exception on failure.     */    public function mapReduce($map, $reduce, $out, $condition = [], $options = [])    {        if (!($map instanceof \MongoCode)) {            $map = new \MongoCode((string) $map);        }        if (!($reduce instanceof \MongoCode)) {            $reduce = new \MongoCode((string) $reduce);        }        $command = [            ‘mapReduce‘ => $this->getName(),            ‘map‘ => $map,            ‘reduce‘ => $reduce,            ‘out‘ => $out        ];        if (!empty($condition)) {            $command[‘query‘] = $this->buildCondition($condition);        }        if (array_key_exists(‘finalize‘, $options)) {            if (!($options[‘finalize‘] instanceof \MongoCode)) {                $options[‘finalize‘] = new \MongoCode((string) $options[‘finalize‘]);            }        }        if (!empty($options)) {            $command = array_merge($command, $options);        }        $token = $this->composeLogToken(‘mapReduce‘, [$map, $reduce, $out]);        Yii::info($token, __METHOD__);        try {            Yii::beginProfile($token, __METHOD__);            $command = array_merge([‘mapReduce‘ => $this->getName()], $command);            $result = $this->mongoCollection->db->command($command);            $this->tryResultError($result);            Yii::endProfile($token, __METHOD__);             return array_key_exists(‘results‘, $result) ? $result[‘results‘] : $result[‘result‘];        } catch (\Exception $e) {            Yii::endProfile($token, __METHOD__);            throw new Exception($e->getMessage(), (int) $e->getCode(), $e);        }    }     /**     * Performs full text search.     * @param string $search string of terms that MongoDB parses and uses to query the text index.     * @param array $condition criteria for filtering a results list.     * @param array $fields list of fields to be returned in result.     * @param array $options additional optional parameters to the mapReduce command. Valid options include:     *  - limit - the maximum number of documents to include in the response (by default 100).     *  - language - the language that determines the list of stop words for the search     *    and the rules for the stemmer and tokenizer. If not specified, the search uses the default     *    language of the index.     * @return array the highest scoring documents, in descending order by score.     * @throws Exception on failure.     */    public function fullTextSearch($search, $condition = [], $fields = [], $options = [])    {        $command = [            ‘search‘ => $search        ];        if (!empty($condition)) {            $command[‘filter‘] = $this->buildCondition($condition);        }        if (!empty($fields)) {            $command[‘project‘] = $fields;        }        if (!empty($options)) {            $command = array_merge($command, $options);        }        $token = $this->composeLogToken(‘text‘, $command);        Yii::info($token, __METHOD__);        try {            Yii::beginProfile($token, __METHOD__);            $command = array_merge([‘text‘ => $this->getName()], $command);            $result = $this->mongoCollection->db->command($command);            $this->tryResultError($result);            Yii::endProfile($token, __METHOD__);             return $result[‘results‘];        } catch (\Exception $e) {            Yii::endProfile($token, __METHOD__);            throw new Exception($e->getMessage(), (int) $e->getCode(), $e);        }    }     /**     * Checks if command execution result ended with an error.     * @param mixed $result raw command execution result.     * @throws Exception if an error occurred.     */    protected function tryResultError($result)    {        if (is_array($result)) {            if (!empty($result[‘errmsg‘])) {                $errorMessage = $result[‘errmsg‘];            } elseif (!empty($result[‘err‘])) {                $errorMessage = $result[‘err‘];            }            if (isset($errorMessage)) {                if (array_key_exists(‘code‘, $result)) {                    $errorCode = (int) $result[‘code‘];                } elseif (array_key_exists(‘ok‘, $result)) {                    $errorCode = (int) $result[‘ok‘];                } else {                    $errorCode = 0;                }                throw new Exception($errorMessage, $errorCode);            }        } elseif (!$result) {            throw new Exception(‘Unknown error, use "w=1" option to enable error tracking‘);        }    }     /**     * Throws an exception if there was an error on the last operation.     * @throws Exception if an error occurred.     */    protected function tryLastError()    {        $this->tryResultError($this->getLastError());    }     /**     * Converts "\yii\db\*" quick condition keyword into actual Mongo condition keyword.     * @param string $key raw condition key.     * @return string actual key.     */    protected function normalizeConditionKeyword($key)    {        static $map = [            ‘AND‘ => ‘$and‘,            ‘OR‘ => ‘$or‘,            ‘IN‘ => ‘$in‘,            ‘NOT IN‘ => ‘$nin‘,        ];        $matchKey = strtoupper($key);        if (array_key_exists($matchKey, $map)) {            return $map[$matchKey];        } else {            return $key;        }    }     /**     * Converts given value into [[MongoId]] instance.     * If array given, each element of it will be processed.     * @param mixed $rawId raw id(s).     * @return array|\MongoId normalized id(s).     */    protected function ensureMongoId($rawId)    {        if (is_array($rawId)) {            $result = [];            foreach ($rawId as $key => $value) {                $result[$key] = $this->ensureMongoId($value);            }             return $result;        } elseif (is_object($rawId)) {            if ($rawId instanceof \MongoId) {                return $rawId;            } else {                $rawId = (string) $rawId;            }        }        try {            $mongoId = new \MongoId($rawId);        } catch (\MongoException $e) {            // invalid id format            $mongoId = $rawId;        }         return $mongoId;    }              public function buildGtCondition($operator, $operands)    {        if (!isset($operands[0], $operands[1])) {            throw new InvalidParamException("Operator ‘$operator‘ requires two operands.");        }        list($column, $value) = $operands;        return [$column => [‘?gt‘ => $value]];    }              public function buildGteCondition($operator, $operands)    {        if (!isset($operands[0], $operands[1])) {            throw new InvalidParamException("Operator ‘$operator‘ requires two operands.");        }        list($column, $value) = $operands;        return [$column => [‘?gte‘ => $value]];    }              public function buildLtCondition($operator, $operands)    {        if (!isset($operands[0], $operands[1])) {            throw new InvalidParamException("Operator ‘$operator‘ requires two operands.");        }        list($column, $value) = $operands;        return [$column => [‘?lt‘ => $value]];    }         public function buildLteCondition($operator, $operands)    {        if (!isset($operands[0], $operands[1])) {            throw new InvalidParamException("Operator ‘$operator‘ requires two operands.");        }        list($column, $value) = $operands;        return [$column => [‘?lte‘ => $value]];    }     /**     * Parses the condition specification and generates the corresponding Mongo condition.     * @param array $condition the condition specification. Please refer to [[Query::where()]]     * on how to specify a condition.     * @return array the generated Mongo condition     * @throws InvalidParamException if the condition is in bad format     */    public function buildCondition($condition)    {        static $builders = [            ‘NOT‘ => ‘buildNotCondition‘,            ‘AND‘ => ‘buildAndCondition‘,            ‘OR‘ => ‘buildOrCondition‘,            ‘BETWEEN‘ => ‘buildBetweenCondition‘,            ‘NOT BETWEEN‘ => ‘buildBetweenCondition‘,            ‘IN‘ => ‘buildInCondition‘,            ‘NOT IN‘ => ‘buildInCondition‘,            ‘REGEX‘ => ‘buildRegexCondition‘,            ‘LIKE‘ => ‘buildLikeCondition‘,            ‘>‘  => ‘buildGtCondition‘,            ‘>=‘ => ‘buildGteCondition‘,            ‘<‘  => ‘buildLtCondition‘,            ‘<=‘     => ‘buildLteCondition‘,        ];         if (!is_array($condition)) {            throw new InvalidParamException(‘Condition should be an array.‘);        } elseif (empty($condition)) {            return [];        }        if (isset($condition[0])) { // operator format: operator, operand 1, operand 2, ...            $operator = strtoupper($condition[0]);            if (isset($builders[$operator])) {                $method = $builders[$operator];                array_shift($condition);                 return $this->$method($operator, $condition);            } else {                throw new InvalidParamException(‘Found unknown operator in query: ‘ . $operator);            }        } else {            // hash format: ‘column1‘ => ‘value1‘, ‘column2‘ => ‘value2‘, ...            return $this->buildHashCondition($condition);        }    }     /**     * Creates a condition based on column-value pairs.     * @param array $condition the condition specification.     * @return array the generated Mongo condition.     */    public function buildHashCondition($condition)    {        $result = [];        foreach ($condition as $name => $value) {            if (strncmp(‘$‘, $name, 1) === 0) {                // Native Mongo condition:                $result[$name] = $value;            } else {                if (is_array($value)) {                    if (array_key_exists(0, $value)) {                        // Quick IN condition:                        $result = array_merge($result, $this->buildInCondition(‘IN‘, [$name, $value]));                    } else {                        // Mongo complex condition:                        $result[$name] = $value;                    }                } else {                    // Direct match:                    if ($name == ‘_id‘) {                        $value = http://www.mamicode.com/$this->ensureMongoId($value);"Operator ‘$operator‘ requires two operands.");        }         list($name, $value) = $operands;         $result = [];        if (is_array($value)) {            $result[$name] = [‘$not‘ => $this->buildCondition($value)];        } else {            if ($name == ‘_id‘) {                $value = http://www.mamicode.com/$this->ensureMongoId($value);"Operator ‘$operator‘ requires three operands.");        }        list($column, $value1, $value2) = $operands;        if (strncmp(‘NOT‘, $operator, 3) === 0) {            return [                $column => [                    ‘$lt‘ => $value1,                    ‘$gt‘ => $value2,                ]            ];        } else {            return [                $column => [                    ‘$gte‘ => $value1,                    ‘$lte‘ => $value2,                ]            ];        }    }     /**     * Creates an Mongo condition with the `IN` operator.     * @param string $operator the operator to use (e.g. `IN` or `NOT IN`)     * @param array $operands the first operand is the column name. If it is an array     * a composite IN condition will be generated.     * The second operand is an array of values that column value should be among.     * @return array the generated Mongo condition.     * @throws InvalidParamException if wrong number of operands have been given.     */    public function buildInCondition($operator, $operands)    {        if (!isset($operands[0], $operands[1])) {            throw new InvalidParamException("Operator ‘$operator‘ requires two operands.");        }         list($column, $values) = $operands;         $values = (array) $values;         if (!is_array($column)) {            $columns = [$column];            $values = [$column => $values];        } elseif (count($column) < 2) {            $columns = $column;            $values = [$column[0] => $values];        } else {            $columns = $column;        }         $operator = $this->normalizeConditionKeyword($operator);        $result = [];        foreach ($columns as $column) {            if ($column == ‘_id‘) {                $inValues = $this->ensureMongoId($values[$column]);            } else {                $inValues = $values[$column];            }            $result[$column][$operator] = array_values($inValues);        }         return $result;    }     /**     * Creates a Mongo regular expression condition.     * @param string $operator the operator to use     * @param array $operands the first operand is the column name.     * The second operand is a single value that column value should be compared with.     * @return array the generated Mongo condition.     * @throws InvalidParamException if wrong number of operands have been given.     */    public function buildRegexCondition($operator, $operands)    {        if (!isset($operands[0], $operands[1])) {            throw new InvalidParamException("Operator ‘$operator‘ requires two operands.");        }        list($column, $value) = $operands;        if (!($value instanceof \MongoRegex)) {            $value = http://www.mamicode.com/new /MongoRegex($value);"Operator ‘$operator‘ requires two operands.");        }        list($column, $value) = $operands;        if (!($value instanceof \MongoRegex)) {            $value = http://www.mamicode.com/new /MongoRegex(‘/‘ . preg_quote($value) . ‘/i‘);>