购物篮Apriori算法的频繁项集产生matlab代码
时间: 2023-10-12 16:20:34 浏览: 100
apriori 频繁项集与关联规则 算法的matlab实现
4星 · 用户满意度95%
以下是使用MATLAB实现Apriori算法的代码,用于生成频繁项集:
```matlab
function [F, items] = freq_itemset_apriori(data, minsup)
% data: a cell array of transactions, each transaction is a row vector of
% item IDs.
% minsup: minimum support threshold
% Get all unique items in the dataset
items = unique([data{:}]);
n = numel(data);
% Initialize frequent itemset
F{1} = items(:);
% Generate frequent itemsets of length > 1
k = 2;
while ~isempty(F{k-1})
% Generate candidate itemsets
C = apriori_gen(F{k-1});
% Count support of candidate itemsets
sup = count_support(C, data);
% Prune infrequent itemsets
F{k} = C(sup >= minsup, :);
k = k + 1;
end
% Remove empty itemsets
F = F(1:end-1);
end
function C = apriori_gen(F)
% Generate candidate itemsets of length k+1 from frequent itemsets of
% length k.
n = size(F, 2);
C = {};
for i = 1:n-1
for j = i+1:n
% Check if the first k-1 items are the same
if all(F(1:end-1,i) == F(1:end-1,j))
% Add the union of the two itemsets
C{end+1} = sort([F(:,i); F(:,j)]);
end
end
end
% Remove duplicates
C = unique(C);
end
function sup = count_support(C, data)
% Count the support of candidate itemsets in the dataset
n = numel(data);
m = numel(C);
sup = zeros(m, 1);
for i = 1:m
itemset = C{i};
for j = 1:n
% Check if the itemset is a subset of the transaction
if all(ismember(itemset, data{j}))
sup(i) = sup(i) + 1;
end
end
end
end
```
请注意,此代码仅生成频繁项集,而不是关联规则。要生成关联规则,您需要编写另一个函数来计算每个频繁项集的关联规则,并选择满足最小置信度阈值的规则。
阅读全文