1.建立資料。

 1 import pandas as pd
 2 import numpy as np
 3 import uuid
 4 import random
 5 
 6 def get_id():
 7     return uuid.uuid1()
 8 
 9 all_data = []
10 for _ in range(1000000):
11     now_id = get_id()
12     all_data.append([now_id, now_id, 3, 4])
13     if random.randint(0,1):
14         all_data.append([now_id, now_id, None, None])
 
15     
16 
17 
18 
19 data = pd.DataFrame(all_data)
20 data.columns = ['name','age','high','breadth']
21 print 'done'

2. 分組聚合

 1 import time
 2 import bottleneck as bk
 3 import multiprocessing
 4 
 5 # def do_pool(func, args):
 6 #     pool = multiprocessing.Pool(2)
 7 #     pool_res = pool.map(func, args)
 

 8 #     pool.close()
 9 #     pool.join()
10 #     return pool_res
11 
12 # def agg_t(df):
13 #     return group.agg(['max'])
14 start = time.time()
15 
16 data_grouped = data.groupby(['name','age']).agg([bk.nanmin])
17 print 'Start aggregation!'
18 
19 # tobe_agg = [group for name, group in data_grouped if len(group) > 1]
 

20 
21 # print len(tobe_agg)
22 print time.time() -start
23 # do_pool(agg_t,tobe_agg)