PHP对象上的空数组属性

Question

This is my class,which reads a csv and store the info in some way

<?php
    class CSV{
        private $data;

        function __construct($filename){
            $this->data = $this->getDataFromFile($filename);
        }

        public function __get($property){

            if(property_exists($this,$property)){
                return $this->$property;
            }
        }



        private function getDataFromFile($filename){
            $new_data = array();
            $result = array();
            if (($handle = fopen($filename,"r")) !== FALSE) {
                while (($data = fgetcsv($handle, 10000, ",")) !== FALSE) {
                    array_push($result, explode(";", $data[0]));;
                }
                fclose($handle);
            }


            $header = $result[0];

            $in_columns = array();
            for ($j = 0 ; $j < count($result[0]); $j++){
                $new = array();
                for ($i = 1 ; $i < count($result); $i++){
                    array_push($new, $result[$i][$j]);
                }
                array_push($in_columns, $new);
            }

            $idx = 0;
            foreach ($header as $title) {
                $new_data[$title] = $in_columns[$idx];
                $idx++; 
            }
            //var_dump($new_data);//the content of $new_data its correct
            $this->data = $new_data;
        }
    }

?>

but wen I try to use the class

$csv = new CSV('./csv/file.csv');
var_dump($csv->__get('data'));

the last var_dump shows a NULL value ¿What is wrong on the assignation of the value?It looks correct for me ,where cold be the problem??

Answer 1

The problem is that your CSV file ends with a blank line ( \\n after the last line).

Thus you're working on an empty array, pushing an unitialized variable (null) into the data array.

Answer 2

You're calling $this->getDataFromFile($filename) in constructor and assigning it's value to $this->data . However... implementation of getDataFromFile() didn't actually return any value, so it's assigning NULL to this property.

You need to change getDataFromFile() to return value OR get rid of variable assignment in constructor - $this->data is already set in your method.

Regarding __get() - it's a magic method . It checks if specified property exists and if so - return it's value. You won't call it this way. Use following code (after making $this->data public):

var_dump($csv->data);

OR prepare accessor for this property which will return this value.