请使用Python写一个apriori算法程序
时间: 2023-06-08 12:03:44 浏览: 100
Python电影智能推荐之Apriori算法(推荐)
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好的,我会尽力回答你的问题。以下是使用Python编写Apriori算法的示例代码:
``` python
def loadDataSet():
# 加载数据集
return [[1, 3, 4], [2, 3, 5], [1, 2, 3, 5], [2, 5]]
def createC1(dataSet):
# 创建初始项集的列表
C1 = []
for transaction in dataSet:
for item in transaction:
if not [item] in C1:
C1.append([item])
C1.sort()
return map(frozenset, C1)
def scanD(D, Ck, minSupport):
# 生成支持度大于minSupport的项集
ssCnt = {}
for tid in D:
for can in Ck:
if can.issubset(tid):
if not ssCnt.has_key(can): ssCnt[can] = 1
else: ssCnt[can] += 1
numItems = float(len(D))
retList = []
supportData = {}
for key in ssCnt:
support = ssCnt[key]/numItems
if support >= minSupport:
retList.insert(0,key)
supportData[key] = support
return retList, supportData
def aprioriGen(Lk, k):
# 创建频繁项集的列表
retList = []
lenLk = len(Lk)
for i in range(lenLk):
for j in range(i+1, lenLk):
L1 = list(Lk[i])[:k-2]; L2 = list(Lk[j])[:k-2]
L1.sort(); L2.sort()
if L1==L2:
retList.append(Lk[i] | Lk[j])
return retList
def apriori(dataSet, minSupport = 0.5):
# 生成频繁项集和关联规则
C1 = createC1(dataSet)
D = map(set, dataSet)
L1, supportData = scanD(D, C1, minSupport)
L = [L1]
k = 2
while (len(L[k-2]) > 0):
Ck = aprioriGen(L[k-2], k)
Lk, supK = scanD(D, Ck, minSupport)
supportData.update(supK)
L.append(Lk)
k += 1
return L, supportData
dataSet = loadDataSet()
L, supportData = apriori(dataSet, minSupport=0.5)
print(L)
print(supportData)
```
这是一个基本的Apriori算法程序,用于在给定的数据集中生成频繁项集和关联规则。请注意,这是一个简单的示例,您可能需要根据自己的需求进行修改和扩展。
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