feifangit

db.zips.aggregate([
    {$project: 
     {
  fc: {$substr : ["$city",0,1]},
	city:1,pop:1
     }	 
   },
{$match:{fc:{$lte:"9",$gte:"0"}}} ,  
   {
         $group: {

feifangit

db.stud.aggregate([
{$match:{"scores.type":{$in:["exam","homework"]}}},
{$unwind:"$scores"},
{$group:{_id:"$class_id",csall:{$avg:"$scores.score"}}},
{$sort:{csall:-1}},
{$limit:5}
]
)

feifangit

import heroku

HEROKU_TOKEN = "xx-xx-xx"  #used for instance restart
APP_NAME = "xxx"
def restart_heroku(auto=False):
    '''restart heroku instance to re-allocate IP'''
    cloud = heroku.from_key(HEROKU_TOKEN)
    app = cloud.apps[APP_NAME]
    for p in app.processes:
        p.restart()