PHP中容易犯错的点

<?php$arr = range(1,3);foreach ($arr as &$v){
}


print_r($arr);foreach ($arr as $v){
    print_r($arr);

}

<?php$data = array();//$data['name']  = 0;//$data['name']  = null;$data['name'] = false;if (isset($data['name'])) {
    var_dump('not set name');
} else {
    var_dump('already set name');

}if (($data['name'])) {
    var_dump('data-name 存在');
} else {
    var_dump('data-name 不存在');

}if (array_key_exists('name', $data)) {
    var_dump('key name 存在于array中');
} else {
    var_dump('key name 不存在于array中');

}

<?phpclass Config{
    private $values = [];    public function __construct() {
        // 使用数组对象而不是数组
        // $this->values = new ArrayObject();
    }    public function &getValues() {
        return $this->values;
    }
}$config = new Config();$config->getValues()['test'] = 'test';echo $config->getValues()['test'];

Notice: Undefined index: test in /Users/leon/Documents/workspace/test/php7.php on line 20

class Config{
    private $values = [];    public function setValue($key, $value) {
        $this->values[$key] = $value;
    }    public function getValue($key) {
        return $this->values[$key];
    }
}$config = new Config();$config->setValue('testKey', 'testValue');echo $config->getValue('testKey');    // 输出『testValue』