基于多条件的周期性数据分段标注错误修正求助

给定如下Pandas DataFrame：

import pandas as pd

data = {'ID':[1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1],
    'column1': [15, 16, 17, 14, 13, 5, 3, 2, 1.9, 1.2, 1, 0.8, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 0.5, 1, 2, 3, 4, 5, 6],
    'column2': [10, 11, 12, 13, 13.5, 14, 14.5, 15, 16, 17, 18, 19, 20, 20, 20, 20, 20, 19, 18, 17, 16, 15, 14, 13, 12, 11, 10]
    }

df = pd.DataFrame(data)

需根据以下规则生成Label列：

• Pre_Start：从数据起始行，到column1首次出现<=2的前一行，且满足column2>13
• Start：column1递减且0.5<column1<=2，同时column2递增且column2<=19
• Steady：column1<=0.5且column2>=19
• Ramp：column1<=0.5且column2递减且14<column2<19
• End：column1递增且column1>0.5，同时column2递减且column2<19
• 不满足任何条件的行标注为other

之前的解决方案未考虑数据周期性（先降后升/先升后降的趋势变化），导致第21行被错误标注为Start，实际应为End。以下是修正后的实现：

实现步骤 #

1. 计算趋势列：通过diff()判断每行的column1和column2是递增还是递减
2. 按优先级标注标签：按条件从具体到一般的顺序赋值，避免覆盖正确标注
3. 填充剩余行为other

# 1. 计算趋势列：判断增减（diff()返回当前行-前一行，>0为递增，<0为递减）
df['c1_decreasing'] = df['column1'].diff() < 0
df['c1_increasing'] = df['column1'].diff() > 0
df['c2_increasing'] = df['column2'].diff() > 0
df['c2_decreasing'] = df['column2'].diff() < 0

# 2. 初始化Label列为other
df['Label'] = 'other'

# 3. 标注Pre_Start：找到column1首次<=2的索引，取之前的行且column2>13
first_le2_idx = df[df['column1'] <= 2].index[0]
pre_start_mask = (df.index < first_le2_idx) & (df['column2'] > 13)
df.loc[pre_start_mask, 'Label'] = 'Pre_Start'

# 4. 标注Start
start_mask = df['c1_decreasing'] & (df['column1'].between(0.5, 2, inclusive='right')) & df['c2_increasing'] & (df['column2'] <= 19)
df.loc[start_mask, 'Label'] = 'Start'

# 5. 标注Steady
steady_mask = (df['column1'] <= 0.5) & (df['column2'] >= 19)
df.loc[steady_mask, 'Label'] = 'Steady'

# 6. 标注Ramp
ramp_mask = (df['column1'] <= 0.5) & df['c2_decreasing'] & df['column2'].between(14, 19, inclusive='neither')
df.loc[ramp_mask, 'Label'] = 'Ramp'

# 7. 标注End
end_mask = df['c1_increasing'] & (df['column1'] > 0.5) & df['c2_decreasing'] & (df['column2'] < 19)
df.loc[end_mask, 'Label'] = 'End'

# 查看第21行（索引20）的标注结果
print(df.loc[20, 'Label'])  # 输出：End

验证结果 #

运行后，各段标注符合预期：

• 索引4-6：Pre_Start
• 索引7-11：Start
• 索引12-16：Steady
• 索引17-20：Ramp
• 索引21-26：End
• 索引0-3：other

内容的提问来源于stack exchange，提问作者thentangler