PHP:strtotime 返回类型为 "nothing"的 "boolean"

Question

我有变量 $EDate，我使用 strtotime 函数和这个具有不同值的变量，结果如下:

$EDate = 10-21-2013;    echo "strtotime($EDate)";   the result = nothing    and the type is boolean
$EDate = 09-02-2013;    echo "strtotime($EDate)";   the result = 1360386000 and the type is integer
$EDate = 09-30-2013;    echo "strtotime($EDate)";   the result = nothing    and the type is boolean
$EDate = 09-30-2013;    echo "strtotime($EDate)";   the result = nothing    and the type is boolean
$EDate = 07-02-2014;    echo "strtotime($EDate)";   the result = 1391749200 and the type is integer
$EDate = 10-12-2014;    echo "strtotime($EDate)";   the result = 1418187600 and the type is integer

谁能解释一下这个以及如何避免 bool 结果？

Answer 1

来自documentation :

Dates in the m/d/y or d-m-y formats are disambiguated by looking at the separator between the various components: if the separator is a slash (/), then the American m/d/y is assumed; whereas if the separator is a dash (-) or a dot (.), then the European d-m-y format is assumed.

您的代码假定日期为 d-m-y 格式，并且由于月份值不正确将返回 FALSE:

var_dump(strtotime('10-21-2013')); // no month 21
var_dump(strtotime('09-30-2013'));
var_dump(strtotime('09-30-2013'));

如果您希望能够使用自定义格式，请使用 DateTime::createFromFormat()相反:

$date = DateTime::createFromFormat('m-d-Y', '10-21-2013');
echo $date->format('U');

Demo!