Clear a field or all fields

# IntlCalendar::clear

(PHP 5 >= 5.5.0, PHP 7, PHP 8, PECL >= 3.0.0a1)

IntlCalendar::clear — Clear a field or all fields

### Beschreibung

Objektorientierter Stil

public function IntlCalendar::clear(?int `$field` = `null`): true

Prozeduraler Stil

function intlcal_clear(IntlCalendar `$calendar`, ?int `$field` = `null`): true

Clears either all of the fields or a specific field. A cleared field is marked as unset, giving it the lowest priority against overlapping fields or even default values when calculating the time. Additionally, its value is set to `0`, though given the fieldʼs low priority, its value may have been internally set to another value by the time the field has finished been queried.

### Parameter-Liste

`calendar`

  Eine IntlCalendar-Instanz.

`field`

  One of the IntlCalendar date/time field constants. These are integer values between `0` and `IntlCalendar::FIELD_COUNT`.

### Rückgabewerte

Gibt immer `true` zurück.

### Changelog

Version | Beschreibung
--- | ---
8.2.0 | Der Rückgabewert ist nun `true` vorher war es bool.

### Beispiele

Beispiel #1 IntlCalendar::clear() examples

    <?php
    ini_set('intl.default_locale', 'es_ES');
    ini_set('date.timezone', 'UTC');

    $fields = array(
        'FIELD_ERA'                  => 0,
        'FIELD_YEAR'                 => 1,
        'FIELD_MONTH'                => 2,
        'FIELD_WEEK_OF_YEAR'         => 3,
        'FIELD_WEEK_OF_MONTH'        => 4,
        'FIELD_DATE'                 => 5,
        'FIELD_DAY_OF_YEAR'          => 6,
        'FIELD_DAY_OF_WEEK'          => 7,
        'FIELD_DAY_OF_WEEK_IN_MONTH' => 8,
        'FIELD_AM_PM'                => 9,
        'FIELD_HOUR'                 => 10,
        'FIELD_HOUR_OF_DAY'          => 11,
        'FIELD_MINUTE'               => 12,
        'FIELD_SECOND'               => 13,
        'FIELD_MILLISECOND'          => 14,
        'FIELD_ZONE_OFFSET'          => 15,
        'FIELD_DST_OFFSET'           => 16,
        'FIELD_YEAR_WOY'             => 17,
        'FIELD_DOW_LOCAL'            => 18,
        'FIELD_EXTENDED_YEAR'        => 19,
        'FIELD_JULIAN_DAY'           => 20,
        'FIELD_MILLISECONDS_IN_DAY'  => 21,
        'FIELD_IS_LEAP_MONTH'        => 22,
        'FIELD_FIELD_COUNT'          => 23,
    );
    function getSetFields(IntlCalendar $cal) {
        global $fields;
        $ret = array();
        foreach ($fields as $name => $value) {
            if ($cal->isSet($value)) {
                $ret[] = $name;
            }
        }
        return $ret;
    }

    $cal = new IntlGregorianCalendar(2013, 2 /* March */, 15);
    echo "After GregorianCalendar creation\n";
    print_r(getSetFields($cal));
    echo "\n";

    echo IntlDateFormatter::formatObject($cal), "\n";
    echo "After the formatter requested the extended year\n";
    print_r(getSetFields($cal));
    echo "\n";

    $cal->clear(IntlCalendar::FIELD_YEAR);
    echo "After the year has been cleared, the date stays the same\n";
    echo IntlDateFormatter::formatObject($cal), "\n";
    echo "because FIELD_EXTENDED_YEAR is still set\n";
    print_r(getSetFields($cal));
    echo "\n";

    var_dump($cal->clear(IntlCalendar::FIELD_EXTENDED_YEAR));
    echo "After the extended year has been cleared\n";
    print_r(getSetFields($cal));
    echo IntlDateFormatter::formatObject($cal), "\n";
    echo "\n";

    echo "After the fields are recalculated,\n"
            . " extended year is set again (to 1970)\n";
    print_r(getSetFields($cal));
    echo "\n";

    $cal->clear();
    echo "After calling variant with no arguments\n";
    print_r(getSetFields($cal));
    echo IntlDateFormatter::formatObject($cal), "\n";

Das oben gezeigte Beispiel erzeugt folgende Ausgabe:

    After GregorianCalendar creation
    Array
    (
        [0] => FIELD_ERA
        [1] => FIELD_YEAR
        [2] => FIELD_MONTH
        [3] => FIELD_DATE
    )

    15/03/2013 00:00:00
    After the formatter requested the extended year
    Array
    (
        [0] => FIELD_ERA
        [1] => FIELD_YEAR
        [2] => FIELD_MONTH
        [3] => FIELD_DATE
        [4] => FIELD_EXTENDED_YEAR
    )

    After the year has been cleared, the date stays the same
    15/03/2013 00:00:00
    because FIELD_EXTENDED_YEAR is still set
    Array
    (
        [0] => FIELD_ERA
        [1] => FIELD_MONTH
        [2] => FIELD_DATE
        [3] => FIELD_EXTENDED_YEAR
    )

    bool(true)
    After the extended year has been cleared
    Array
    (
        [0] => FIELD_ERA
        [1] => FIELD_MONTH
        [2] => FIELD_DATE
    )
    15/03/1970 00:00:00

    After the fields are recalculated,
     extended year is set again (to 1970)
    Array
    (
        [0] => FIELD_ERA
        [1] => FIELD_MONTH
        [2] => FIELD_DATE
        [3] => FIELD_EXTENDED_YEAR
    )

    After calling variant with no arguments
    Array
    (
    )
    01/01/1970 00:00:00

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