数学模子公式:
$$ \sum{i=1}^{n} xi $$
此中,Σ表现求和操纵,x表现数据值,n表现数据的个数。
4.详细代码实例和详细表明说明
4.1Python实现Join算法
python def join(R1, R2, C, D): result = [] for r in R1: for s in R2: if r[C] == s[D]: result.append(r + s) return result
4.2Python实现出非常值算法
python def outlier_detection(data, attribute, threshold): mean = np.mean(data[attribute]) std = np.std(data[attribute]) result = [] for x in data[attribute]: z_score = (x - mean) / std if abs(z_score) > threshold: result.append(x) return result
4.3Python实现映射算法
python def mapping(data, source_format, target_format): mapping_dict = {} for i, x in enumerate(source_format): mapping_dict[x] = target_format result = [] for x in data: new_x = [] for y in x: new_x.append(mapping_dict[y]) result.append(new_x) return result
4.4Python实现聚合算法