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Ds\Sequence::first

(PECL ds >= 1.0.0)

Ds\Sequence::first — Returns the first value in the sequence

说明

abstract public Ds\Sequence::first(): mixed

Returns the first value in the sequence.

参数

此函数没有参数。

返回值

The first value in the sequence.

错误／异常

UnderflowException if empty.

示例

示例 #1 Ds\Sequence::first() example

<?php
$sequence = new \Ds\Vector([1, 2, 3]);
var_dump($sequence->first());
?>

以上示例的输出类似于：

int(1)