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How does one write a shorthand setter in PHP?
$value = "Which array do I go in?";
if(true)
    $arr_1[] = $value;
else
    $arr_2[] = $value;

(true)?$arr_1[]:$arr_2[] = "Which array do I go in?";

${$cond?'arr_1':'arr_2'}[] = $value;

$GLOBALS[cond ? 'varname1' : 'varname2'] = $value;

$arr = ($cond ? &$arr_1 : &$arr_2);
$arr[] = 'Which array do I go in';

$cond ? $arr_1[] = $value : $arr_2[] = $value;