accessing an object instance by only having one of its attribute values

[feli.hp at gmail.com]

Hello all,

Imaybe someone can help me with this question.
Is there a direct way of accessing an object instance, if all I know
is the value of one of its attributes?
The object is part of a list of objects, and I would like to pick the
object directly by using this attribute value, instead of going
through the list and checking if each objects attribute value is the
one I am looking for.

Thank you in advance