[英]Why doesn't the function work with my input?
我有一個默認的示例字典,看起來像這樣:
critics = {'Lisa Rose': {'Lady in the Water': 2.5, 'Snakes on a Plane': 3.5,
'Just My Luck': 3.0, 'Superman Returns': 3.5, 'You, Me and Dupree': 2.5,
'The Night Listener': 3.0},
'Gene Seymour': {'Lady in the Water': 3.0, 'Snakes on a Plane': 3.5,
'Just My Luck': 1.5, 'Superman Returns': 5.0, 'The Night Listener': 3.0,
'You, Me and Dupree': 3.5},
'Michael Phillips': {'Lady in the Water': 2.5, 'Snakes on a Plane': 3.0,
'Superman Returns': 3.5, 'The Night Listener': 4.0},
'Claudia Puig': {'Snakes on a Plane': 3.5, 'Just My Luck': 3.0,
'The Night Listener': 4.5, 'Superman Returns': 4.0,
'You, Me and Dupree': 2.5},
'Mick LaSalle': {'Lady in the Water': 3.0, 'Snakes on a Plane': 4.0,
'Just My Luck': 2.0, 'Superman Returns': 3.0, 'The Night Listener': 3.0,
'You, Me and Dupree': 2.0},
'Jack Matthews': {'Lady in the Water': 3.0, 'Snakes on a Plane': 4.0,
'The Night Listener': 3.0, 'Superman Returns': 5.0, 'You, Me and Dupree': 3.5},
'Toby': {'Snakes on a Plane':4.5,'You, Me and Dupree':1.0,'Superman Returns':4.0}}
我使用的函數使用如下所示的Pearson相關系數返回字典中最相似的人:
from math import sqrt
def sim_pearson(prefs,p1,p2):
# lista na zaednichki tochki
si={}
for item in prefs[p1]:
if item in prefs[p2]: si[item]=1
# najdi go brojot na elementi
n=len(si)
# ako nemaat zaednichki tochki vrati 0
if n==0: return 0
# dodadi gi site
sum1=sum([prefs[p1][it] for it in si])
sum2=sum([prefs[p2][it] for it in si])
# sumiraj gi kvadratite
sum1Sq=sum([pow(prefs[p1][it],2) for it in si])
sum2Sq=sum([pow(prefs[p2][it],2) for it in si])
# sumiraj gi proizvodite
pSum=sum([prefs[p1][it]*prefs[p2][it] for it in si])
# presmetka na Pirsonoviot koeficient
num=pSum-(sum1*sum2/n)
den=sqrt((sum1Sq-pow(sum1,2)/n)*(sum2Sq-pow(sum2,2)/n))
if den==0: return 0
r=num/den
return r
而且有效。 例如,對於調用print sim_pearson(critics, 'Toby', 'Lisa Rose')
我得到系數0.991240707162。
但是,當我嘗試使用與字典相同的功能時:
tests = {'dzam': {'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiKAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjvAQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj3AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiMAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiBAgw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjtAQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj_AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiIAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj9AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiqAgw': 3.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjzAQw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxikAgw': 3.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiaAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj1AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjxAQw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiYAgw': 5.0},
'kex': {'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiKAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjvAQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj3AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiMAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiBAgw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjtAQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj_AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiIAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj9AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiqAgw': 3.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjzAQw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxikAgw': 3.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiaAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj1AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjxAQw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiYAgw': 5.0},
'rokoko': {'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiKAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjvAQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj3AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiMAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiBAgw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjtAQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj_AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiIAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj9AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiqAgw': 3.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjzAQw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxikAgw': 3.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiaAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj1AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjxAQw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiYAgw': 5.0},
'test@example.com': {'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiKAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjvAQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj3AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiMAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiBAgw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjtAQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj_AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiIAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj9AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiqAgw': 3.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjzAQw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxikAgw': 3.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiaAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxj1AQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjxAQw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiYAgw': 5.0},
'seljak': {'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiKAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjvAQw': 1.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxiKAgw': 5.0,
'ag1yYW5kb20tcmFuZG9tcg8LEghib29rbWFyaxjvAQw': 1.0, }}
我總是得到1.0,無論字典中是否有匹配項,為什么會這樣?
順便說一句,我正在使用哈希,因此我的字典必須具有此長字符串。 :)
您可能會被長長的鍵所迷惑,這些鍵對眼睛隱藏着哪些不同的字符串。
嘗試在測試'seljak'
所有值都設置為0
並對其進行關聯。 您會看到0
相關性:
print sim_pearson(tests, 'test@example.com', 'seljak')
將測試'seljak'
的最后一個值更改為1,您將看到負相關重新運行腳本。
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