php生成器的使用

引用和参考 https://learnku.com/articles/1430/single-php-generator-complete-knowledge-generator-implementation-process

迭代和迭代器

迭代是指反复执行一个过程,每执行一次叫做一次迭代.

 '#FF0000',
    'green' => '#00FF00',
    'blue'  => '#0000FF'
];

foreach ($mapping as $key => $value) {
    printf("key: %d - value: %s\n", $key, $value);
}