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简介
Generator 对象是从 generators返回的.
CautionGenerator 对象不能通过 new 实例化.
类摘要
Generator implements Iterator
{
/* 方法 */
public current ( void ) : mixed
public key ( void ) : mixed
public next ( void ) : void
public rewind ( void ) : void
public send ( mixed $value ) : mixed
public throw ( Exception $exception ) : void
public valid ( void ) : bool
public __wakeup ( void ) : void
}
Unlike return, yield can be used anywhere within a function so logic can flow more naturally. Take for example the following Fibonacci generator:
<?php
function fib($n)
{
$cur = 1;
$prev = 0;
for ($i = 0; $i < $n; $i++) {
yield $cur;
$temp = $cur;
$cur = $prev + $cur;
$prev = $temp;
}
}
$fibs = fib(9);
foreach ($fibs as $fib) {
echo " " . $fib;
}
// prints: 1 1 2 3 5 8 13 21 34