To solve the problem, the foreach loop array will only move the pointer once to the second place,

& Amp; lt ;? Php $ countries [{code...}]; foreach ($ countriesas $ key & amp; gt; $ value) {code ...}}? & Amp; gt;

$ Countries = [

        [            '0' => [                'id' =>0            ]        ],        [            '1' => [                'id' =>1            ]        ],

];
Foreach ($ countries as $ key => $ value ){

Print_r (current ($ countries); echo 'next'; print_r (pos ($ countries); next ($ countries); echo PHP_EOL;

}
?>

Reply content:

$ Countries = [

        [            '0' => [                'id' =>0            ]        ],        [            '1' => [                'id' =>1            ]        ],

];
Foreach ($ countries as $ key => $ value ){

Print_r (current ($ countries); echo 'next'; print_r (pos ($ countries); next ($ countries); echo PHP_EOL;

}
?>

Defined$countriesAnd in the foreach loop$countriesPoint to the same zval variable, because PHP needs to save memory, and does not need to store the same data in two copies. In this caserefcount2. but if it is changed in the loop$countriesFor example

Foreach ($ countries as & $ country) {$ country = 'China'; // because the value assignment operation is performed here, copy-on-write}

Or

Foreach ($ countries as $ country) {echo current ($ countries); // because current is to be referenced, copy-on-write} occurs here}

Passed the reference and assigned a value, which is triggeredcopy-on-writeOperation, that is, copy the zval to the original zvalrefcountMinus 1.

The current statement is executed every time a loop occurs.copy-on-writeSo each current operation is a new zval.

Same as this answer