hi Anna,
yes, you can do this and for example, we're doing this in the classification if you import osm files.
select the layer into which the street segments are imported, then in the Inspector, you can go grab the Object Attributes which came in with the SHP file.
an example :
class = getObjectAttr("class")
attr streetWidth =
case class == "highway":
true
else:
false
an example like this would make it possible to select all graph segments which have the attribute "class" with the value highway ( which is true )
the selection itself is then done in the viewport by RMB-->select by Map Layer.
play with this a little, ok ?
let me know how it goes !