Why does strtotime returns a date with some strange string?-CodePudding

I was testing some strings (countries) with the

strtotime()

function and foud out that :

'Poland' does returns a timestamp, but 'Soland' or anything else like this does not.
'GB' does too.

Going farther, 'a string' is also returning something, juste like some simple Letters like 'G' or 'P'.

Those strings are not listed in the datetime relative formats doc.

I might be dumb but I didn't find anything on those special cases, what is actually going on ?

And second less important question : how to actually check if a string is a valid date format excluding those "special" strings, knowing I don't know the format in advance ?

CodePudding user response：

DateTime accepts the same arguments as strtotime. The argument 'GB' used for DateTime shows that 'GB' is recognized as the time zone.

var_dump(new DateTime('GB'));
/*
object(DateTime)#3 (3) {
  ["date"]=>
  string(26) "2021-09-24 16:54:37.568996"
  ["timezone_type"]=>
  int(3)
  ["timezone"]=>
  string(2) "GB"
}
*/

Like 'Poland', 'GB' is also represented in the list of Others time zones. 'Soland' not. DateTime then provides the current time ('Now') for a correctly recognized time zone.