变量键名

Can I check for a variable key without using a temporary variable.

$var = 'blabla';
$key = "{$var}_abc";

if(isset($someobject->$key))...

?

with arrays you can do this... $array["{$var}_abc"]

Yes. You can use curly braces containing an expression resulting in a string, where that string is the name of the property you want to check.

$someobject->{"{$var}_abc"}
$someobject->{$var."_abc"}

yes, try enclosing the variable in braces

Edit: not paranthesis, braces..

You can employ braces around the member name:

if (isset($someobject->{$var.'_abc'}))

you can use concatenation like $array[$var."_abc"]

You can do this, using property_exists() method

if(property_exists($object, $var."_abc")) {
 // do stuff
}