I have a collection of objects, which i want to separate into groups
based on a particular property (to be specific, two attributes - that is
if obj.foo and obj.bar are both the same for two objects they go into an
array together). Not every object has a duplicate, but most of them do.
So, i’d end up with an array, where each member is another array, with
the subarrays holding either 1 or 2 (or maybe more) objects that match
on foo and bar.
Can anyone tell me a nice and simple way of doing this?
Can anyone tell me a nice and simple way of doing this?
Enumerable#parition or Set#classify might help.
– fxn
hmmm…i couldn’t work out how to make it easier with either of those.
I ended up doing this, which isn’t very clever but it did seem to work.
groups = []
vals = collection.collect{|obj| [obj.val1, obj.val2]}.uniq!
for val in vals
groups << collection.select{|obj| obj.val1 == val[0] && obj.val2 =
val[1]
end
The activesupport gem, which is part of Rails, but can be used
separately, adds an Enumerable#group_by method which does pretty much
what you are asking for if I understand correctly.
hmmm…i couldn’t work out how to make it easier with either of those.
I ended up doing this, which isn’t very clever but it did seem to work.
groups = []
vals = collection.collect{|obj| [obj.val1, obj.val2]}.uniq!
for val in vals
groups << collection.select{|obj| obj.val1 == val[0] && obj.val2 =
val[1]
end
The activesupport gem, which is part of Rails, but can be used
separately, adds an Enumerable#group_by method which does pretty much
what you are asking for if I understand correctly.
hmmm…i couldn’t work out how to make it easier with either of those.
I ended up doing this, which isn’t very clever but it did seem to
work.
groups = []
vals = collection.collect{|obj| [obj.val1, obj.val2]}.uniq!
for val in vals
groups << collection.select{|obj| obj.val1 == val[0] && obj.val2 =
val[1]
Note there is an assignment instead of an equals operator there.
cheers!