# DatePeriod::__construct

(PHP 5 >= 5.3.0, PHP 7, PHP 8)

DatePeriod::__construct — Creates a new DatePeriod object

### 说明

public DatePeriod::__construct(
DateTimeInterface `$start`,
DateInterval `$interval`,
int `$recurrences`,
int `$options` = 0
)
public DatePeriod::__construct(
DateTimeInterface `$start`,
DateInterval `$interval`,
DateTimeInterface `$end`,
int `$options` = 0
)
警告

The following constructor variant has been deprecated:

public DatePeriod::__construct(string `$isostr`, int `$options` = 0)

Instead the DatePeriod::createFromISO8601String() static factory method should be used.

Creates a new DatePeriod object.

DatePeriod objects can be used as an iterator to generate a number of DateTimeImmutable or DateTime object from a `start` date, a `interval`, and an `end` date or the number of `recurrences`.

The class of returned objects is equivalent to the DateTimeImmutable or DateTime ancestor class of the `start` object.

### 参数

`start`

  The start date of the period. Included by default in the result set.

`interval`

  The interval between recurrences within the period.

`recurrences`

  The number of recurrences. The number of returned results is one higher than this, as the start date is included in the result set by default. Must be greater than `0`.

`end`

  The end date of the period. Excluded by default from the result set.

`isostr`

  A subset of the » ISO 8601 repeating interval specification.

  Examples of some ISO 8601 interval specification features that PHP does not support are:

  1. zero occurrences (`R0/`)
  2. time offsets other than UTC (`Z`), such as `+02:00`.
`options`

  A bit field which can be used to control certain behaviour with start- and end- dates.

  With `DatePeriod::EXCLUDE_START_DATE` you exclude the start date from the set of recurring dates within the period.

  With `DatePeriod::INCLUDE_END_DATE` you include the end date in the set of recurring dates within the period.

### 错误／异常

Throws an DateMalformedPeriodStringException when the `isostr` cannot be parsed as a valid ISO 8601 period. Prior to PHP 8.3, this was Exception.

### 更新日志

版本 | 说明
--- | ---
8.3.0 | Now throws DateMalformedPeriodStringException instead of Exception.
8.2.0 | The `DatePeriod::INCLUDE_END_DATE` constant has been added.
7.2.19, 7.3.6, 7.4.0 | `recurrences` must be greater than `0` now.

### 示例

示例 #1 DatePeriod example

`<?php
$start = new DateTime('2012-07-01');
$interval = new DateInterval('P7D');
$end = new DateTime('2012-07-31');
$recurrences = 4;
$iso = 'R4/2012-07-01T00:00:00Z/P7D';
// All of these periods are equivalent.
$period = new DatePeriod($start, $interval, $recurrences);
$period = new DatePeriod($start, $interval, $end);
$period = new DatePeriod($iso);
// By iterating over the DatePeriod object, all of the
// recurring dates within that period are printed.
foreach ($period as $date) {
echo $date->format('Y-m-d')."\n";
}`

以上示例会输出：

    Deprecated: Calling DatePeriod::__construct(string $isostr, int $options = 0) is deprecated, use DatePeriod::createFromISO8601String() instead in script on line 11
    2012-07-01
    2012-07-08
    2012-07-15
    2012-07-22
    2012-07-29

示例 #2 DatePeriod example with `DatePeriod::EXCLUDE_START_DATE`

`<?php
$start = new DateTime('2012-07-01');
$interval = new DateInterval('P7D');
$end = new DateTime('2012-07-31');
$period = new DatePeriod($start, $interval, $end,
DatePeriod::EXCLUDE_START_DATE);
// By iterating over the DatePeriod object, all of the
// recurring dates within that period are printed.
// Note that, in this case, 2012-07-01 is not printed.
foreach ($period as $date) {
echo $date->format('Y-m-d')."\n";
}`

以上示例会输出：

    2012-07-08
    2012-07-15
    2012-07-22
    2012-07-29

示例 #3 DatePeriod example showing all last Thursdays in a year

`<?php
$begin = new DateTime('2021-12-31');
$end = new DateTime('2022-12-31 23:59:59');
$interval = DateInterval::createFromDateString('last thursday of next month');
$period = new DatePeriod($begin, $interval, $end, DatePeriod::EXCLUDE_START_DATE);
foreach ($period as $dt) {
echo $dt->format('l Y-m-d'), "\n";
}`

以上示例会输出：

    Thursday 2022-01-27
    Thursday 2022-02-24
    Thursday 2022-03-31
    Thursday 2022-04-28
    Thursday 2022-05-26
    Thursday 2022-06-30
    Thursday 2022-07-28
    Thursday 2022-08-25
    Thursday 2022-09-29
    Thursday 2022-10-27
    Thursday 2022-11-24
    Thursday 2022-12-29

### 注释

Unbound numbers of repetitions as specified by ISO 8601 section 4.5 "Recurring time interval" are not supported, i.e. neither passing `"R/..."` as `isostr` nor passing `null` as `end` would work.

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