src/Zend/Filter/NormalizedToLocalized.php
public function filter($value)
    {
        if (is_array($value)) {

            $date = new Zend_Date($value, $this->_options['locale']);
            return $date->toString($this->_options['date_format']);
        } else if ($this->_options['precision'] === 0) {
            return Zend_Locale_Format::toInteger($value, $this->_options);
        } else if ($this->_options['precision'] === null) {
            return Zend_Locale_Format::toFloat($value, $this->_options);
        }

        return Zend_Locale_Format::toNumber($value, $this->_options);
    }
public function filter($value)
    {
        if (is_array($value)) {

            $date = new Zend_Date($value, $this->_options['locale']);
            return $date->toString($this->_options['date_format']);
        } else if ($this->_options['precision'] === 0) {
            return Zend_Locale_Format::toInteger($value, $this->_options);
        } else if ($this->_options['precision'] === null) {
            return Zend_Locale_Format::toFloat($value, $this->_options);
        }

        return Zend_Locale_Format::toNumber($value, $this->_options);
    }
Defined by Zend_Filter_Interface

Normalizes the given input

@param  string $value Value to normalized
@return string|array The normalized value