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<?php $def = [ 'country' => ['cz', 'de', 'hu'] ]; var_dump(json_encode($def));
Output for 7.0.0 - 7.0.20, 7.1.0 - 7.1.33, 7.2.0 - 7.2.33, 7.3.0 - 7.3.33, 7.4.0 - 7.4.33, 8.0.0 - 8.0.30, 8.1.0 - 8.1.28, 8.2.0 - 8.2.18, 8.3.0 - 8.3.6
string(28) "{"country":["cz","de","hu"]}"
preferences:
169.25 ms | 403 KiB | 200 Q