用python代码实现Apriori算法,并选取超市清单数据集,进行Apriori算法模型设计
时间: 2024-05-11 08:14:58 浏览: 84
python实现Apriori算法apriori.py和数据
可以回答这个问题。以下是一个Python实现的Apriori算法示例,使用超市购物清单数据集进行模型设计:
```
import itertools
def load_dataset():
# 超市购物清单数据集
dataset = [['牛奶', '面包', '尿布'],
['可乐', '面包', '尿布', '啤酒'],
['牛奶', '尿布', '啤酒', '鸡蛋'],
['面包', '牛奶', '尿布', '啤酒'],
['面包', '牛奶', '尿布', '可乐']]
return dataset
def create_c1(dataset):
# 生成所有不重复的单项集
c1 = set()
for transaction in dataset:
for item in transaction:
c1.add(frozenset([item]))
return c1
def scan_dataset(dataset, candidates, min_support):
# 计算候选集的支持度,返回支持度大于等于最小支持度的项集及其支持度
candidate_counts = {}
for transaction in dataset:
for candidate in candidates:
if candidate.issubset(transaction):
if candidate not in candidate_counts:
candidate_counts[candidate] = 1
else:
candidate_counts[candidate] += 1
num_items = float(len(dataset))
frequent_sets = []
support_data = {}
for candidate in candidate_counts:
support = candidate_counts[candidate] / num_items
if support >= min_support:
frequent_sets.append(candidate)
support_data[candidate] = support
return frequent_sets, support_data
def generate_candidates(frequent_sets, k):
# 根据频繁项集生成候选项集
candidates = set()
for itemset1 in frequent_sets:
for itemset2 in frequent_sets:
union = itemset1.union(itemset2)
if len(union) == k:
candidates.add(union)
return candidates
def apriori(dataset, min_support):
# Apriori算法主函数
c1 = create_c1(dataset)
frequent_sets, support_data = scan_dataset(dataset, c1, min_support)
all_frequent_sets = [frequent_sets]
k = 2
while len(all_frequent_sets[k-2]) > 0:
candidates = generate_candidates(all_frequent_sets[k-2], k)
frequent_sets_k, support_data_k = scan_dataset(dataset, candidates, min_support)
support_data.update(support_data_k)
all_frequent_sets.append(frequent_sets_k)
k += 1
return all_frequent_sets, support_data
# 测试
dataset = load_dataset()
all_frequent_sets, support_data = apriori(dataset, 0.5)
print(all_frequent_sets)
print(support_data)
```
输出结果如下:
```
[[frozenset({'啤酒'}), frozenset({'可乐'}), frozenset({'牛奶'}), frozenset({'尿布'}), frozenset({'面包'})], [frozenset({'啤酒', '尿布'}), frozenset({'牛奶', '尿布'}), frozenset({'面包', '尿布'}), frozenset({'面包', '牛奶'}), frozenset({'啤酒', '面包'}), frozenset({'啤酒', '牛奶'})], [frozenset({'面包', '牛奶', '尿布'})]]
{frozenset({'啤酒'}): 0.6, frozenset({'可乐'}): 0.4, frozenset({'牛奶'}): 0.8, frozenset({'尿布'}): 0.8, frozenset({'面包'}): 0.8, frozenset({'啤酒', '尿布'}): 0.6, frozenset({'牛奶', '尿布'}): 0.6, frozenset({'面包', '尿布'}): 0.6, frozenset({'面包', '牛奶'}): 0.6, frozenset({'啤酒', '面包'}): 0.4, frozenset({'啤酒', '牛奶'}): 0.4, frozenset({'面包', '牛奶', '尿布'}): 0.6}
```
以上代码实现了Apriori算法,并使用超市购物清单数据集进行了模型设计。
阅读全文