ctype_digit

<?php     public function toBeDigits(string $message = ''): self

    {

        Assert::assertTrue(ctype_digit((string) $this->value), $message);



        return $this;

    }

<?php         $args = $input->getArgument('args');



        if (null !== $timeout = $input->getOption('timeout')) {

            if (!ctype_digit($timeout)) {

                throw new \RuntimeException('Timeout value must be numeric and positive if defined, or 0 for forever');

            }

<?php     public function __construct(string $data)

    {

        if (ctype_digit($data)) {

            $this->status = (int)$data;

        } else {

            $this->content = $data;