11.2. How to work with currencies

11.2. How to work with currencies
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To use Zend_Currency within the own application just create an instance of it without any parameter. This will create an instance of Zend_Currency with the actual locale, and defines the currency which has to be used for this locale.

Example 11.1. Creating an instance of Zend_Currency from the actual locale

Expect you have 'en_US' set as actual locale through the users or your environment. By using no parameter while creating the instance you say Zend_Currency to use the actual currency from the locale 'en_US'. This leads to an instance with US Dollar set as actual currency with the formatting rules from 'en_US'.

$currency = new Zend_Currency();

Since Zend Framework 1.7.0 Zend_Currency does also support the usage of an application wide locale. You can simply set a Zend_Locale instance to the registry like shown below. With this notation you can forget about setting the locale manually with each instance when you want to use the same locale multiple times.

// in your bootstrap file
$locale = new Zend_Locale('de_AT');
Zend_Registry::set('Zend_Locale', $locale);

// somewhere in your application
$currency = new Zend_Currency();

	Note
	Be aware, that if your system has no default locale, or if the locale of your system can not be detected automatically, `Zend_Currency` will throw an exception. If you have this behaviour you should set the locale you manually.

Of course, depending on your needs, several parameters can be given at creation. Each of this parameters is optional and can be suppressed. Even the order of the parameters can be switched. The meaning of each parameter is described in this list:

currency:

A locale can include several currencies. Therefor the first parameter 'currency' can define which currency should be used by giving the short name or full name of that currency. If that currency in not known in any locale an exception will be thrown. Currency short names are always 3 lettered and written uppercase. Well known currency shortnames are for example USD or EUR. For a list of all known currencies see the informational methods of Zend_Currency.

locale:

The third parameter 'locale' defines which locale should be used for formatting the currency. The given locale will also be used to get the standard script and currency of this currency if these parameters are not given.

	Note
	Note that Zend_Currency only accepts locales which include a region. This means that all given locale which only include the language will throw an exception. For example the locale en will throw an exception whereas the locale en_US will return USD as currency.

Example 11.2. Other examples for creating an instance of Zend_Currency

// expect standard locale 'de_AT'

// creates an instance from 'en_US' using 'USD' which is default
// currency for 'en_US'
$currency = new Zend_Currency('en_US');

// creates an instance from the actual locale ('de_AT') using 'EUR' as
// currency
$currency = new Zend_Currency();

// creates an instance using 'EUR' as currency, 'en_US' for number
// formating
$currency = new Zend_Currency('en_US', 'EUR');

So you can supress any of these parameters if you want to use the default ones. This has no negative effect on handling the currencies. It can be useful f.e. if you don't know the default currency for a region.

	Note
	For many countries there are several known currencies. One currency will actually be used and maybe several ancient currencies. If the 'currency' parameter is suppressed the actual currency will be used. The region 'de' for example knows the currencies 'EUR' and 'DEM'... 'EUR' is the actual one and will be used if the parameter is suppressed.

11.2.1. Create output from an currency

To get an existing value converted to a currency formatted output the method toCurrency() can be used. It takes a value which should be converted. The value itself can be any normalized number.

If you have a localized number you will have to convert it first to an normalized number with Zend_Locale_Format::getNumber(). Afterwards it can be used with toCurrency() to create an currency output.

toCurrency(array $options) accepts an array with options which can be used to temporary set another format or currency representation. For details about which options can be used see Changing the format of a currency.

Example 11.3. Creating output for an currency

// creates an instance with 'en_US' using 'USD' which is the default
// values for 'en_US'
$currency = new Zend_Currency('en_US');

// prints '$ 1,000.00'
echo $currency->toCurrency(1000);

// prints '$ 1.000,00'
echo $currency->toCurrency(1000, array('format' => 'de_AT'));

// prints '$ ١٬٠٠٠٫٠٠'
echo $currency->toCurrency(1000, array('script' => 'Arab'));

11.2.2. Changing the format of a currency

The format which is used by creation of a Zend_Currency instance is of course the standard format. But sometimes it is necessary to change this format for own purposes.

The format of an currency output includes the following parts:

Currency symbol, shortname or name:

The symbol of the currency is normally displayed within an currency output. It can be suppressed when needed or even overwritten.
Currency position:

The position of the currency sign is normally automatically defined by the locale. It can be changed if necessary.
Script:

The script which shall be used to display digits. Detailed information about scripts and their usage can be found in the documentation of Zend_Locale in supported number scripts.
Number formatting:

The amount of currency (formally known as value of money) is formatted by the usage of formatting rules within the locale. For example is in English the ',' sign used as separator for thousands, and in German the '.' sign.

So if you are in need to change the format, you can use the setFormat() method. It takes an array which includes all options which you want to change. The options array supports the following settings:

position: Defines the position at which the currency description should be displayed. The supported position can be found in this table.
script: Defined which script has to be used for displaying digits. The default script for most locales is 'Latn', which includes the digits 0 to 9. Also other scripts like 'Arab' (Arabian) can be used. All supported scripts can be found in this table.
format: Defines which locale has to be used for displaying numbers. This number-format includes for example the thousand separator. If no format is set the locale from the Zend_Currency object will be used.
display: Defines which part of the currency has to be used for displaying the currency representation. There are 4 representations which can be used and which are all described in this table.
precision: Defines the precision which has to be used for the currency representation. The default value is 2.
name: Defines the full currency name which has to be displayed. This option overwrites any currency name which is set through the creation of Zend_Currency.
currency: Defines the international abbreviation which has to be displayed. This option overwrites any abbreviation which is set through the creation of Zend_Currency.
symbol: Defines the currency symbol which has to be displayed. This option overwrites any symbol which is set through the creation of Zend_Currency.

Table 11.1. Constants for the selecting the currency description

constant	description
NO_SYMBOL	Do not display any currency representation
USE_SYMBOL	Display the currency symbol
USE_SHORTNAME	Display the 3 lettered international currency abbreviation
USE_NAME	Display the full currency name

Table 11.2. Constants for the selecting the currency position

constant	description
STANDARD	Set the standard position as defined within the locale
RIGHT	Display the currency representation at the right side of the value
LEFT	Display the currency representation at the left side of the value

Example 11.4. Changing the displayed format of a currency

// creates an instance with 'en_US' using 'USD', 'Latin' and 'en_US' as
// these are the default values from 'en_US'
$currency = new Zend_Currency('en_US');

// prints 'US$ 1,000.00'
echo $currency->toCurrency(1000);

$currency->setFormat('display' => Zend_Currency::USE_NAME,
                     'position' => Zend_Currency::RIGHT);

// prints '1.000,00 US Dollar'
echo $currency->toCurrency(1000);

$currency->setFormat('name' => 'American Dollar');
// prints '1.000,00 American Dollar'
echo $currency->toCurrency(1000);

11.2.3. Informational methods for Zend_Currency

Of course, Zend_Currency supports also methods to get informations about any existing and many ancient currencies from Zend_Locale. The supported methods are:

getSymbol():

Returns the known sign of the actual currency or a given currency. For example $ for the US Dollar within the locale 'en_US.
getShortName():

Returns the abbreviation of the actual currency or a given currency. For example USD for the US Dollar within the locale 'en_US.
getName():

Returns the full name of the actual currency of a given currency. For example US Dollar for the US Dollar within the locale 'en_US.
getRegionList():

Returns a list of regions where the actual currency or a given one is known to be used. It is possible that a currency is used within several regions therefor the return value is always an array.
getCurrencyList():

Returns a list of currencies which are known to be used in the given region.

The function getSymbol(), getShortName() and getName() accept two optional parameters. If no parameter is given the expected data will be returned from the actual set currency. The first parameter takes the shortname of a currency. Short names are always three lettered, for example EUR for euro or USD for US Dollar. The second parameter defines from which locale the data should be read. If no locale is given, the actual set locale is used.

Example 11.5. Getting informations from currencies

// creates an instance with 'en_US' using 'USD', 'Latin' and 'en_US'
// as these are the default values from 'en_US'
$currency = new Zend_Currency('en_US');

// prints '$'
echo $currency->getSymbol();

// prints 'EUR'
echo $currency->getShortName('EUR');

// prints 'Österreichische Schilling'
echo $currency->getName('ATS', 'de_AT');

// returns an array with all regions where USD is used
print_r($currency->getRegionList();

// returns an array with all currencies which were ever used in this
// region
print_r($currency->getCurrencyList('de_AT');

11.2.4. Settings new default values

The method setLocale allows to set a new locale for Zend_Currency. When calling this function also all default values for the currency will be overwritten. This includes currency name, abbreviation and symbol.

Example 11.6. Setting a new locale

// get the currency for US
$currency = new Zend_Currency('en_US');
print $currency->toCurrency(1000);

// get the currency for AT
$currency->setLocale('de_AT');
print $currency->toCurrency(1000);

11.2.5. Speed up Zend_Currency

The work of Zend_Currency can be speed up by the usage of Zend_Cache. By using the static method Zend_Currency::setCache($cache) which accepts one option, an Zend_Cache adapter. When you set it, the localization data of the methods from Zend_Currency are cached. For convenience there are the static methods getCache(), hasCache(), clearCache() and removeCache().

Example 11.7. Caching currencies

// creating a cache object
$cache = Zend_Cache::factory('Core',
                             'File',
                             array('lifetime' => 120,
                                   'automatic_serialization' => true),
                             array('cache_dir'
                                       => dirname(__FILE__) . '/_files/'));
Zend_Currency::setCache($cache);