熊猫：透视表

Question

我有DF：

ID,url,used_at,active_seconds,domain,search_engine,diff_time,period,code, category 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/product/12858630?hid=91491&track=fr_same,2016-03-20 23:19:49,6,yandex.ru,None,78.0,515,100.0, Search system 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/product/12858630?hid=91491&track=fr_same,2016-03-20 23:20:01,26,yandex.ru,None,6.0,515,100.0, Social network 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/catalog/54726/list?hid=91491&track=pieces&gfilter=1801946%3A1871375&exc=1&regprice=9&how=dpop,2016-03-20 23:20:33,14,yandex.ru,None,6.0,515,100.0, Social network 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/product/12858630/offers?hid=91491&grhow=shop,2016-03-20 23:20:47,2,yandex.ru,None,14.0,515,100.0, Internet shop 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/product/12858630/offers?hid=91491&grhow=shop,2016-03-20 23:24:05,8,yandex.ru,None,196.0,515,100.0, Internet shop 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/catalogmodels.xml?hid=91491&CAT_ID=160043&nid=54726&track=pieces,2016-03-20 23:24:13,32,yandex.ru,None,8.0,515,100.0, Search system 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/catalog/54726/list?hid=91491&track=fr_cm_shwall&exc=1&how=dpop,2016-03-20 23:24:45,16,yandex.ru,None,32.0,515,100.0, Internet shop 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/catalogmodels.xml?hid=91491&CAT_ID=160043&nid=54726&track=pieces,2016-03-20 23:25:01,4,yandex.ru,None,16.0,515,100.0, Search system 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/catalog/54726/list?hid=91491&track=fr_cm_pop&exc=1&how=dpop,2016-03-20 23:25:05,10,yandex.ru,None,4.0,515,100.0, Social network 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/product/11153512?hid=91491&track=fr_same,2016-03-21 06:52:44,2,yandex.ru,None,14.0,516,100.0, Internet shop 
08cd0141663315ce71e0121e3cd8d91f,market.yandex.ru/catalog/54726/list?hid=91491&track=pieces&gfilter=1801946%3A1871375&exc=1&regprice=9&how=dpop,2016-04-04 21:08:41,24,yandex.ru,None,20.0,562,100.0, Internet shop 
0bc0898d3fe2e46158621c674effb458,market.yandex.ru/product/12259780?hid=91491&show-uid=56508001849064882783001,2016-02-26 20:34:20,28,yandex.ru,yandex,10.0,1217,100.0, Social network 
0bc0898d3fe2e46158621c674effb458,market.yandex.ru/product/12259780?hid=91491&show-uid=56508001849064882783001,2016-02-26 20:34:50,1,yandex.ru,None,2.0,1217,100.0, Internet shop 

我需要建立pivot_table。 我用

table = pd.pivot_table(df, values='domain', index=['ID'], columns=['category'], aggfunc=np.sum) 

但问题在于它加到domain，但我想算唯一域的控管数量。我怎样才能做到这一点？

Answer 1

它看起来像需要：

table = pd.pivot_table(df, values='domain', 
          index=['ID'], 
          columns=['category'], 
          aggfunc=lambda x: x.nunique()) 
print (table) 

category       Internet shop Search system \ 
ID                 
08cd0141663315ce71e0121e3cd8d91f    1.0    1.0 
0bc0898d3fe2e46158621c674effb458    1.0    NaN 

category       Social network 
ID             
08cd0141663315ce71e0121e3cd8d91f    1.0 
0bc0898d3fe2e46158621c674effb458    1.0 

另一种更快的解决方案：

print (df.groupby(['ID','category'])['domain'].nunique().unstack()) 
category       Internet shop Search system \ 
ID                 
08cd0141663315ce71e0121e3cd8d91f    1.0    1.0 
0bc0898d3fe2e46158621c674effb458    1.0    NaN 

category       Social network 
ID             
08cd0141663315ce71e0121e3cd8d91f    1.0 
0bc0898d3fe2e46158621c674effb458    1.0