试一试:

$date = "2017-10-01";


function date_checker($input,$devider){
  $output = false;

  $input = explode($devider, $input);
  $year = $input[0];
  $month = $input[1];
  $day = $input[2];

  if (is_numeric($year) && is_numeric($month) && is_numeric($day)) {
    if (strlen($year) == 4 && strlen($month) == 2 && strlen($day) == 2) {
      $output = true;
    }
  }
  return $output;
}

if (date_checker($date, '-')) {
  echo "The function is working";
}else {
  echo "The function isNOT working";
}

使用php预构建函数的简单方式:

function checkmydate($date) {
  $tempDate = explode('-', $date);
  // checkdate(month, day, year)
  return checkdate($tempDate[1], $tempDate[2], $tempDate[0]);
}

Test

   checkmydate('2015-12-01'); //true
   checkmydate('2015-14-04'); //false

要添加到已接受的答案上，可以通过检查格式化的日期是否是DateTime的实例来进一步检查有效日期或DateTime。

$date = DateTime::createFromFormat('Ymd', $value);
$is_datetime = ($date instanceof DateTime);
$is_valid_datetime_format = $is_datetime
  ? ($date->format('Ymd') === $value)
  : false;

if (!$is_datetime || !$is_valid_datetime_format) {
  // Not a valid date.
  return false;
}

这将捕获任何不是DateTime的值，如随机字符串或无效日期，如20202020。

判断字符串是否为日期，即使字符串是非标准格式

(strtotime不接受任何自定义格式)

<?php
function validateDateTime($dateStr, $format)
{
    date_default_timezone_set('UTC');
    $date = DateTime::createFromFormat($format, $dateStr);
    return $date && ($date->format($format) === $dateStr);
}

// These return true
validateDateTime('2001-03-10 17:16:18', 'Y-m-d H:i:s');
validateDateTime('2001-03-10', 'Y-m-d');
validateDateTime('2001', 'Y');
validateDateTime('Mon', 'D');
validateDateTime('March 10, 2001, 5:16 pm', 'F j, Y, g:i a');
validateDateTime('March 10, 2001, 5:16 pm', 'F j, Y, g:i a');
validateDateTime('03.10.01', 'm.d.y');
validateDateTime('10, 3, 2001', 'j, n, Y');
validateDateTime('20010310', 'Ymd');
validateDateTime('05-16-18, 10-03-01', 'h-i-s, j-m-y');
validateDateTime('Monday 8th of August 2005 03:12:46 PM', 'l jS \of F Y h:i:s A');
validateDateTime('Wed, 25 Sep 2013 15:28:57', 'D, d M Y H:i:s');
validateDateTime('17:03:18 is the time', 'H:m:s \i\s \t\h\e \t\i\m\e');
validateDateTime('17:16:18', 'H:i:s');

// These return false
validateDateTime('2001-03-10 17:16:18', 'Y-m-D H:i:s');
validateDateTime('2001', 'm');
validateDateTime('Mon', 'D-m-y');
validateDateTime('Mon', 'D-m-y');
validateDateTime('2001-13-04', 'Y-m-d');

测试过的Regex解决方案:

    function isValidDate($date)
    {
            if (preg_match("/^(((((1[26]|2[048])00)|[12]\d([2468][048]|[13579][26]|0[48]))-((((0[13578]|1[02])-(0[1-9]|[12]\d|3[01]))|((0[469]|11)-(0[1-9]|[12]\d|30)))|(02-(0[1-9]|[12]\d))))|((([12]\d([02468][1235679]|[13579][01345789]))|((1[1345789]|2[1235679])00))-((((0[13578]|1[02])-(0[1-9]|[12]\d|3[01]))|((0[469]|11)-(0[1-9]|[12]\d|30)))|(02-(0[1-9]|1\d|2[0-8])))))$/", $date)) {
                    return $date;
            }
            return null;
    }

如果日期无效或不是yyyy-mm-dd格式，将返回null，否则将返回日期。

试试这个:

$myday = '2022-1-30'; 
if (($timestamp = strtotime($myday)) === false) {
    echo 'The string ('.$myday.') is not date';
} else {
    echo 'The string ('.$myday.') is date = ' . date('l dS \o\f F Y h:i:s A', $timestamp);
}