$parentId == 0 && $str_group ? eval("$nstr = \"$str_group\";") : eval("$nstr = \"$str\";");
What does == in this line of code mean
==
Ternary operator, equivalent to
if($parentId == 0 && $str) { eval("$nstr = \"$str\";"); } else { eval("$nstr = \"$str\";"); }
Ternary operator, equivalent to