ArrayAccess::offsetExists

(PHP 5, PHP 7)

ArrayAccess::offsetExists — 锟斤拷锟揭伙拷锟狡拷锟轿伙拷锟斤拷欠锟斤拷锟斤拷

说锟斤拷

abstract public ArrayAccess::offsetExists ( mixed $offset ) : boolean

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锟斤拷一锟斤拷实锟斤拷锟斤拷 ArrayAccess 锟接口的讹拷锟斤拷使锟斤拷 isset() 锟斤拷 empty() 时锟斤拷锟剿凤拷锟斤拷锟斤拷执锟叫★拷

Note:

锟斤拷使锟斤拷 empty() 锟斤拷锟揭斤拷锟斤拷 ArrayAccess::offsetExists() 锟斤拷锟斤拷 TRUE 时锟斤拷ArrayAccess::offsetGet() 锟斤拷锟斤拷锟斤拷锟斤拷锟皆硷拷锟斤拷锟轿拷锟秸★拷

锟斤拷锟斤拷

offset

锟斤拷要锟斤拷锟斤拷偏锟斤拷位锟矫★拷

锟斤拷锟斤拷值

锟缴癸拷时锟斤拷锟斤拷 TRUE锟斤拷 锟斤拷锟斤拷锟斤拷失锟斤拷时锟斤拷锟斤拷 FALSE锟斤拷

Note:

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Example #1 ArrayAccess::offsetExists() 锟斤拷锟斤拷

<?php
class obj implements arrayaccess {
    public function offsetSet($offset, $value) {
        var_dump(__METHOD__);
    }
    public function offsetExists($var) {
        var_dump(__METHOD__);
        if ($var == "foobar") {
            return true;
        }
        return false;
    }
    public function offsetUnset($var) {
        var_dump(__METHOD__);
    }
    public function offsetGet($var) {
        var_dump(__METHOD__);
        return "value";
    }
}

$obj = new obj;

echo "Runs obj::offsetExists()\n";
var_dump(isset($obj["foobar"]));

echo "\nRuns obj::offsetExists() and obj::offsetGet()\n";
var_dump(empty($obj["foobar"]));

echo "\nRuns obj::offsetExists(), *not* obj:offsetGet() as there is nothing to get\n";
var_dump(empty($obj["foobaz"]));
?>

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Runs obj::offsetExists()
string(17) "obj::offsetExists"
bool(true)

Runs obj::offsetExists() and obj::offsetGet()
string(17) "obj::offsetExists"
string(14) "obj::offsetGet"
bool(false)

Runs obj::offsetExists(), *not* obj:offsetGet() as there is nothing to get
string(17) "obj::offsetExists"
bool(true)