validation - Rails validate multiple attributes lambda only if all of them present -

i need validate few attributes in model when present in params while updating or creating object.

 validates :attribute_a,format: {with: /some_regex/},  :if => lambda{ |object| object.attribute_a.present? } 

like attribute_a there multiple attributes may not present while being created or updated.instead of writing validates statement each of them,is there way in can check presence of multiple attributes , validate every 1 common validation such inclusion_inor format:{with:/some_regex/ }.

i wanted following code wrong.

validates :attribute_a,attribute_b,attribute_c,attribute_d,:format => {:with =>  /some_regex/},  :if => lambda{ |object| object.attribute_name.present? } 

you can use validates_format_of:

validates_format_of :attr_a, :attr_b,      with: /someregexp/,     allow_blank: true 

the allow blank option means regexp doesn't have match if attribute not present.