将条件应用于循环（熊猫）时出现值错误

Question

while (i< len(df)):
    if (df['ID'][i] == df['ID'][i+1]) & (df['Week_start'] == df['Week_end']):
        if (df['ship'][i]  > df['ship'][i+1] ):
            df['radar'][i] =df['radar'][i+1] + df['parked'][i] - df['parked'][i+1]
        else:
            df['radar'][i] =df['radar'][i+1]
    else:
        df['radar'][i] = df['ship'][i]
    i = i+1

我试图使此代码运行，但我不断遇到错误：

  

ValueError：DataFrame的真值不明确。使用a.empty，a.bool（），a.item（），a.any（）或a.all（）。

您推荐什么？本质上，我想根据条件填充柱状雷达，我认为其余的工作正常。

Answer 1

您在此行中收到错误：

df['Week_start'] == df['Week_end']

指定一些索引，例如

df['Week_start'][i]== df['Week_end'][i+1]

希望这会有所帮助！