Sequence
PHP Manual

Ds\Sequence::first

(PECL ds >= 1.0.0)

Ds\Sequence::firstReturns the first value in the sequence.

说明

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

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.

范例

Example #1 Ds\Sequence::first() example

<?php
$sequence 
= new \Ds\Vector([123]);
var_dump($sequence->first());
?>

以上例程的输出类似于:

int(1)

Sequence
PHP Manual