Implement avgby.

[zehome]

Fixes #30

[Dieterbe]

looks good. other than that one thing i commented in the code. i like how the code modifies graph_config instead of graphs[graph_key]

[Dieterbe]

great work. as you can see i did a few extra smaller commits.

[Dieterbe]

i pushed some more things, including that check for tags appearing in more then one of avg/sum/group by. have a look at my commits and let me know what you think.

could you also explain why you need a copy @

all_targets = graph_config['targets'][:]  # Get a copy

[zehome]

Sure,

because of this line:

+                    for t in targets:
+                        all_targets.remove(t)

In python if you do:

for i in mylist:
  mylist.remove(x)

You NEED to get a copy of mylist or the forloop will go crazy. So you do a copy of the list before iterating on it :)

[Dieterbe]

but that targets variable is actually coming from

for (avg_id, targets) in graph_config['targets_avg_candidates'].items():

not from graph_config['targets'] so it's a different list

[zehome]

That's right, anyway the code don't use/remove stuff from all_targets from the same loop, so it should be safe to use directly. It's probably overkill to get a copy so.